This is an automated email from the ASF dual-hosted git repository.

ggregory pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-io.git


The following commit(s) were added to refs/heads/master by this push:
     new 547e8c9  Use assertThrows() in tests instead of custom try/catch 
blocks.
547e8c9 is described below

commit 547e8c9ca7e6900c0cdfb9fa2fc3df9f8da83d2b
Author: Gary Gregory <gardgreg...@gmail.com>
AuthorDate: Wed Sep 22 10:30:39 2021 -0400

    Use assertThrows() in tests instead of custom try/catch blocks.
---
 .../apache/commons/io/FileCleaningTrackerTest.java |  38 +---
 .../apache/commons/io/FileDeleteStrategyTest.java  |  15 +-
 .../org/apache/commons/io/FileSystemUtilsTest.java | 188 +++---------------
 .../java/org/apache/commons/io/FileUtilsTest.java  |  12 +-
 .../java/org/apache/commons/io/IOCaseTest.java     |  87 ++------
 .../org/apache/commons/io/IOUtilsWriteTest.java    |  94 ++-------
 .../commons/io/filefilter/FileFilterTest.java      | 221 +++------------------
 .../commons/io/filefilter/RegexFileFilterTest.java |  32 +--
 .../io/filefilter/WildcardFileFilterTest.java      |  20 +-
 .../commons/io/output/LockableFileWriterTest.java  |  90 ++++-----
 10 files changed, 165 insertions(+), 632 deletions(-)

diff --git a/src/test/java/org/apache/commons/io/FileCleaningTrackerTest.java 
b/src/test/java/org/apache/commons/io/FileCleaningTrackerTest.java
index ae405b6..1e46d64 100644
--- a/src/test/java/org/apache/commons/io/FileCleaningTrackerTest.java
+++ b/src/test/java/org/apache/commons/io/FileCleaningTrackerTest.java
@@ -19,6 +19,7 @@ package org.apache.commons.io;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
@@ -32,6 +33,7 @@ import java.nio.file.Files;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.apache.commons.io.filefilter.PrefixFileFilter;
 import org.apache.commons.io.test.TestUtils;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
@@ -183,12 +185,8 @@ public class FileCleaningTrackerTest {
 
         final String path = testFile.getPath();
         final Object marker = new Object();
-        try {
-            theInstance.track(path, marker);
-            fail();
-        } catch (final IllegalStateException ex) {
-            // expected
-        }
+        
+        assertThrows(IllegalStateException.class, () -> 
theInstance.track(path, marker));
         assertTrue(theInstance.exitWhenFinished);
         assertNull(theInstance.reaper);
     }
@@ -298,30 +296,10 @@ public class FileCleaningTrackerTest {
     }
     @Test
     public void testFileCleanerNull() {
-        try {
-            theInstance.track((File) null, new Object());
-            fail();
-        } catch (final NullPointerException ex) {
-            // expected
-        }
-        try {
-            theInstance.track((File) null, new Object(), 
FileDeleteStrategy.NORMAL);
-            fail();
-        } catch (final NullPointerException ex) {
-            // expected
-        }
-        try {
-            theInstance.track((String) null, new Object());
-            fail();
-        } catch (final NullPointerException ex) {
-            // expected
-        }
-        try {
-            theInstance.track((String) null, new Object(), 
FileDeleteStrategy.NORMAL);
-            fail();
-        } catch (final NullPointerException ex) {
-            // expected
-        }
+        assertThrows(NullPointerException.class, () -> 
theInstance.track((File) null, new Object()));
+        assertThrows(NullPointerException.class, () -> 
theInstance.track((File) null, new Object(), FileDeleteStrategy.NORMAL));
+        assertThrows(NullPointerException.class, () -> 
theInstance.track((String) null, new Object()));
+        assertThrows(NullPointerException.class, () -> 
theInstance.track((String) null, new Object(), FileDeleteStrategy.NORMAL));
     }
 
     private void waitUntilTrackCount() throws Exception {
diff --git a/src/test/java/org/apache/commons/io/FileDeleteStrategyTest.java 
b/src/test/java/org/apache/commons/io/FileDeleteStrategyTest.java
index 6dd3d62..ecaf323 100644
--- a/src/test/java/org/apache/commons/io/FileDeleteStrategyTest.java
+++ b/src/test/java/org/apache/commons/io/FileDeleteStrategyTest.java
@@ -18,6 +18,7 @@ package org.apache.commons.io;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
@@ -83,12 +84,7 @@ public class FileDeleteStrategyTest {
         assertTrue(subDir.exists());
         assertTrue(subFile.exists());
         // delete dir
-        try {
-            FileDeleteStrategy.NORMAL.delete(subDir);
-            fail();
-        } catch (final IOException ex) {
-            // expected
-        }
+        assertThrows(IOException.class, () -> 
FileDeleteStrategy.NORMAL.delete(subDir));
         assertTrue(subDir.exists());
         assertTrue(subFile.exists());
         // delete file
@@ -105,12 +101,7 @@ public class FileDeleteStrategyTest {
 
     @Test
     public void testDeleteNull() throws Exception {
-        try {
-            FileDeleteStrategy.NORMAL.delete(null);
-            fail();
-        } catch (final NullPointerException ex) {
-            // expected
-        }
+        assertThrows(NullPointerException.class, () -> 
FileDeleteStrategy.NORMAL.delete(null));
         assertTrue(FileDeleteStrategy.NORMAL.deleteQuietly(null));
     }
 
diff --git a/src/test/java/org/apache/commons/io/FileSystemUtilsTest.java 
b/src/test/java/org/apache/commons/io/FileSystemUtilsTest.java
index 5765b61..0aa0374 100644
--- a/src/test/java/org/apache/commons/io/FileSystemUtilsTest.java
+++ b/src/test/java/org/apache/commons/io/FileSystemUtilsTest.java
@@ -147,46 +147,23 @@ public class FileSystemUtilsTest {
     @Test
     public void testGetFreeSpaceOS_String_InitError() throws Exception {
         final FileSystemUtils fsu = new FileSystemUtils();
-        try {
-            fsu.freeSpaceOS("", -1, false, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IllegalStateException ignore) {
-        }
-        try {
-            fsu.freeSpaceOS("", -1, true, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IllegalStateException ignore) {
-        }
+        assertThrows(IllegalStateException.class, () -> fsu.freeSpaceOS("", 
-1, false, NEG_1_TIMEOUT));
+        assertThrows(IllegalStateException.class, () -> fsu.freeSpaceOS("", 
-1, true, NEG_1_TIMEOUT));
     }
 
     @Test
     public void testGetFreeSpaceOS_String_NullPath() throws Exception {
         final FileSystemUtils fsu = new FileSystemUtils();
-        try {
-            fsu.freeSpaceOS(null, 1, false, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-        try {
-            fsu.freeSpaceOS(null, 1, true, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
+        assertThrows(IllegalArgumentException.class, () -> 
fsu.freeSpaceOS(null, 1, false, NEG_1_TIMEOUT));
+        assertThrows(IllegalArgumentException.class, () -> 
fsu.freeSpaceOS(null, 1, true, NEG_1_TIMEOUT));
     }
 
     @Test
     public void testGetFreeSpaceOS_String_Other() throws Exception {
         final FileSystemUtils fsu = new FileSystemUtils();
-        try {
-            fsu.freeSpaceOS("", 0, false, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IllegalStateException ignore) {
-        }
-        try {
-            fsu.freeSpaceOS("", 0, true, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IllegalStateException ignore) {
-        }
+        assertThrows(IllegalStateException.class, () -> fsu.freeSpaceOS("", 0, 
false, NEG_1_TIMEOUT));
+        assertThrows(IllegalArgumentException.class, () -> 
fsu.freeSpaceOS(null, 1, true, NEG_1_TIMEOUT));
+        assertThrows(IllegalStateException.class, () -> fsu.freeSpaceOS("", 0, 
true, NEG_1_TIMEOUT));
     }
 
     @Test
@@ -219,27 +196,10 @@ public class FileSystemUtilsTest {
                 "Filesystem           1K-blocks      Used Available Use% 
Mounted on\n" +
                         "xxx:/home/users/s     14428928  12956424   1472504  
90% /home/users/s";
         final FileSystemUtils fsu = new MockFileSystemUtils(0, lines);
-        try {
-            fsu.freeSpaceUnix("", false, false, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("", true, false, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("", true, true, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("", false, true, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-
+        assertThrows(IllegalArgumentException.class, () -> 
fsu.freeSpaceUnix("", false, false, NEG_1_TIMEOUT));
+        assertThrows(IllegalArgumentException.class, () -> 
fsu.freeSpaceUnix("", true, false, NEG_1_TIMEOUT));
+        assertThrows(IllegalArgumentException.class, () -> 
fsu.freeSpaceUnix("", true, true, NEG_1_TIMEOUT));
+        assertThrows(IllegalArgumentException.class, () -> 
fsu.freeSpaceUnix("", false, true, NEG_1_TIMEOUT));
     }
 
     @Test
@@ -247,26 +207,10 @@ public class FileSystemUtilsTest {
     public void testGetFreeSpaceUnix_String_EmptyResponse() {
         final String lines = "";
         final FileSystemUtils fsu = new MockFileSystemUtils(0, lines);
-        try {
-            fsu.freeSpaceUnix("/home/users/s", false, false, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("/home/users/s", true, false, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("/home/users/s", false, true, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("/home/users/s", true, true, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", false, false, NEG_1_TIMEOUT));
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", true, false, NEG_1_TIMEOUT));
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", false, true, NEG_1_TIMEOUT));
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", true, true, NEG_1_TIMEOUT));
     }
 
     @Test
@@ -275,26 +219,10 @@ public class FileSystemUtilsTest {
                 "Filesystem           1K-blocks      Used Available Use% 
Mounted on\n" +
                         "                      14428928  12956424       100";
         final FileSystemUtils fsu = new MockFileSystemUtils(0, lines);
-        try {
-            fsu.freeSpaceUnix("/home/users/s", false, false, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("/home/users/s", true, false, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("/home/users/s", false, true, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("/home/users/s", true, true, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", false, false, NEG_1_TIMEOUT));
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", true, false, NEG_1_TIMEOUT));
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", false, true, NEG_1_TIMEOUT));
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", true, true, NEG_1_TIMEOUT));
     }
 
     @Test
@@ -303,26 +231,10 @@ public class FileSystemUtilsTest {
                 "Filesystem           1K-blocks      Used Available Use% 
Mounted on\n" +
                         "xxx:/home/users/s     14428928  12956424   nnnnnnn  
90% /home/users/s";
         final FileSystemUtils fsu = new MockFileSystemUtils(0, lines);
-        try {
-            fsu.freeSpaceUnix("/home/users/s", false, false, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("/home/users/s", true, false, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("/home/users/s", false, true, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("/home/users/s", true, true, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", false, false, NEG_1_TIMEOUT));
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", true, false, NEG_1_TIMEOUT));
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", false, true, NEG_1_TIMEOUT));
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", true, true, NEG_1_TIMEOUT));
     }
 
     @Test
@@ -331,26 +243,10 @@ public class FileSystemUtilsTest {
                 "Filesystem           1K-blocks      Used Available Use% 
Mounted on\n" +
                         "xxx:/home/users/s     14428928  12956424        -1  
90% /home/users/s";
         final FileSystemUtils fsu = new MockFileSystemUtils(0, lines);
-        try {
-            fsu.freeSpaceUnix("/home/users/s", false, false, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("/home/users/s", true, false, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("/home/users/s", false, true, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("/home/users/s", true, true, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", false, false, NEG_1_TIMEOUT));
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", true, false, NEG_1_TIMEOUT));
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", false, true, NEG_1_TIMEOUT));
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", true, true, NEG_1_TIMEOUT));
     }
 
     @Test
@@ -359,26 +255,10 @@ public class FileSystemUtilsTest {
                 "Filesystem           1K-blocks      Used Available Use% 
Mounted on\n" +
                         "xxx-yyyyyyy-zzz:/home/users/s";
         final FileSystemUtils fsu = new MockFileSystemUtils(0, lines);
-        try {
-            fsu.freeSpaceUnix("/home/users/s", false, false, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("/home/users/s", true, false, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("/home/users/s", false, true, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
-        try {
-            fsu.freeSpaceUnix("/home/users/s", true, true, NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", false, false, NEG_1_TIMEOUT));
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", true, false, NEG_1_TIMEOUT));
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", false, true, NEG_1_TIMEOUT));
+        assertThrows(IOException.class, () -> 
fsu.freeSpaceUnix("/home/users/s", true, true, NEG_1_TIMEOUT));
     }
 
     @Test
@@ -483,11 +363,7 @@ public class FileSystemUtilsTest {
     public void testGetFreeSpaceWindows_String_EmptyResponse() {
         final String lines = "";
         final FileSystemUtils fsu = new MockFileSystemUtils(0, lines);
-        try {
-            fsu.freeSpaceWindows("C:", NEG_1_TIMEOUT);
-            fail();
-        } catch (final IOException ignore) {
-        }
+        assertThrows(IOException.class, () -> fsu.freeSpaceWindows("C:", 
NEG_1_TIMEOUT));
     }
 
     @Test
diff --git a/src/test/java/org/apache/commons/io/FileUtilsTest.java 
b/src/test/java/org/apache/commons/io/FileUtilsTest.java
index d959601..ce3fdfc 100644
--- a/src/test/java/org/apache/commons/io/FileUtilsTest.java
+++ b/src/test/java/org/apache/commons/io/FileUtilsTest.java
@@ -364,11 +364,7 @@ public class FileUtilsTest {
     @Test
     public void test_openInputStream_notExists() {
         final File directory = new File(temporaryFolder, "test.txt");
-        try (FileInputStream in = FileUtils.openInputStream(directory)) {
-            fail();
-        } catch (final IOException ioe) {
-            // expected
-        }
+        assertThrows(IOException.class, () -> 
FileUtils.openInputStream(directory));
     }
 
     @Test
@@ -418,11 +414,7 @@ public class FileUtilsTest {
                         "abcdevwxyzabcdevwxyzabcdevwxyzabcdevwxyzabcdevwxyz" +
                         "abcdevwxyzabcdevwxyzabcdevwxyzabcdevwxyzabcdevwxyz";  
// 300 chars
         final File file = new File(temporaryFolder, "a/" + longStr + 
"/test.txt");
-        try (FileOutputStream out = FileUtils.openOutputStream(file)) {
-            fail();
-        } catch (final IOException ioe) {
-            // expected
-        }
+        assertThrows(IOException.class, () -> 
FileUtils.openOutputStream(file));
     }
 
     // byteCountToDisplaySize
diff --git a/src/test/java/org/apache/commons/io/IOCaseTest.java 
b/src/test/java/org/apache/commons/io/IOCaseTest.java
index 7ea9bf1..0193eca 100644
--- a/src/test/java/org/apache/commons/io/IOCaseTest.java
+++ b/src/test/java/org/apache/commons/io/IOCaseTest.java
@@ -19,12 +19,14 @@ package org.apache.commons.io;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
+import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 
@@ -74,18 +76,9 @@ public class IOCaseTest {
         assertEquals(0, IOCase.SENSITIVE.checkCompareTo("ABC", "ABC"));
         assertEquals(0, IOCase.SENSITIVE.checkCompareTo("", ""));
 
-        try {
-            IOCase.SENSITIVE.checkCompareTo("ABC", null);
-            fail();
-        } catch (final NullPointerException ignore) {}
-        try {
-            IOCase.SENSITIVE.checkCompareTo(null, "ABC");
-            fail();
-        } catch (final NullPointerException ignore) {}
-        try {
-            IOCase.SENSITIVE.checkCompareTo(null, null);
-            fail();
-        } catch (final NullPointerException ignore) {}
+        assertThrows(NullPointerException.class, () -> 
IOCase.SENSITIVE.checkCompareTo("ABC", null));
+        assertThrows(NullPointerException.class, () -> 
IOCase.SENSITIVE.checkCompareTo(null, "ABC"));
+        assertThrows(NullPointerException.class, () -> 
IOCase.SENSITIVE.checkCompareTo(null, null));
     }
 
     @Test
@@ -140,18 +133,9 @@ public class IOCaseTest {
         assertFalse(IOCase.SENSITIVE.checkEquals("", "ABC"));
         assertTrue(IOCase.SENSITIVE.checkEquals("", ""));
 
-        try {
-            IOCase.SENSITIVE.checkEquals("ABC", null);
-            fail();
-        } catch (final NullPointerException ignore) {}
-        try {
-            IOCase.SENSITIVE.checkEquals(null, "ABC");
-            fail();
-        } catch (final NullPointerException ignore) {}
-        try {
-            IOCase.SENSITIVE.checkEquals(null, null);
-            fail();
-        } catch (final NullPointerException ignore) {}
+        assertThrows(NullPointerException.class, () -> 
IOCase.SENSITIVE.checkEquals("ABC", null));
+        assertThrows(NullPointerException.class, () -> 
IOCase.SENSITIVE.checkEquals(null, "ABC"));
+        assertThrows(NullPointerException.class, () -> 
IOCase.SENSITIVE.checkEquals(null, null));
     }
 
 
@@ -206,18 +190,9 @@ public class IOCaseTest {
         // too long
         assertEquals(-1,   IOCase.SENSITIVE.checkIndexOf("DEF", 0, 
"ABCDEFGHIJ"));
 
-        try {
-            IOCase.SENSITIVE.checkIndexOf("ABC", 0, null);
-            fail();
-        } catch (final NullPointerException ignore) {}
-        try {
-            IOCase.SENSITIVE.checkIndexOf(null, 0, "ABC");
-            fail();
-        } catch (final NullPointerException ignore) {}
-        try {
-            IOCase.SENSITIVE.checkIndexOf(null, 0, null);
-            fail();
-        } catch (final NullPointerException ignore) {}
+        assertThrows(NullPointerException.class, () -> 
IOCase.SENSITIVE.checkIndexOf("ABC", 0, null));
+        assertThrows(NullPointerException.class, () -> 
IOCase.SENSITIVE.checkIndexOf(null, 0, "ABC"));
+        assertThrows(NullPointerException.class, () -> 
IOCase.SENSITIVE.checkIndexOf(null, 0, null));
     }
 
     @Test
@@ -254,30 +229,12 @@ public class IOCaseTest {
         assertFalse(IOCase.SENSITIVE.checkRegionMatches("", 1, "ABC"));
         assertFalse(IOCase.SENSITIVE.checkRegionMatches("", 1, ""));
 
-        try {
-            IOCase.SENSITIVE.checkRegionMatches("ABC", 0, null);
-            fail();
-        } catch (final NullPointerException ignore) {}
-        try {
-            IOCase.SENSITIVE.checkRegionMatches(null, 0, "ABC");
-            fail();
-        } catch (final NullPointerException ignore) {}
-        try {
-            IOCase.SENSITIVE.checkRegionMatches(null, 0, null);
-            fail();
-        } catch (final NullPointerException ignore) {}
-        try {
-            IOCase.SENSITIVE.checkRegionMatches("ABC", 1, null);
-            fail();
-        } catch (final NullPointerException ignore) {}
-        try {
-            IOCase.SENSITIVE.checkRegionMatches(null, 1, "ABC");
-            fail();
-        } catch (final NullPointerException ignore) {}
-        try {
-            IOCase.SENSITIVE.checkRegionMatches(null, 1, null);
-            fail();
-        } catch (final NullPointerException ignore) {}
+        assertThrows(NullPointerException.class, () -> 
IOCase.SENSITIVE.checkRegionMatches("ABC", 0, null));
+        assertThrows(NullPointerException.class, () -> 
IOCase.SENSITIVE.checkRegionMatches(null, 0, "ABC"));
+        assertThrows(NullPointerException.class, () -> 
IOCase.SENSITIVE.checkRegionMatches(null, 0, null));
+        assertThrows(NullPointerException.class, () -> 
IOCase.SENSITIVE.checkRegionMatches("ABC", 1, null));
+        assertThrows(NullPointerException.class, () -> 
IOCase.SENSITIVE.checkRegionMatches(null, 1, "ABC"));
+        assertThrows(NullPointerException.class, () -> 
IOCase.SENSITIVE.checkRegionMatches(null, 1, null));
     }
 
     @Test
@@ -314,14 +271,8 @@ public class IOCaseTest {
         assertEquals(IOCase.SENSITIVE, IOCase.forName("Sensitive"));
         assertEquals(IOCase.INSENSITIVE, IOCase.forName("Insensitive"));
         assertEquals(IOCase.SYSTEM, IOCase.forName("System"));
-        try {
-            IOCase.forName("Blah");
-            fail();
-        } catch (final IllegalArgumentException ignore) {}
-        try {
-            IOCase.forName(null);
-            fail();
-        } catch (final IllegalArgumentException ignore) {}
+        assertThrows(IllegalArgumentException.class, () -> 
IOCase.forName("Blah"));
+        assertThrows(IllegalArgumentException.class, () -> 
IOCase.forName(null));
     }
 
     @Test
diff --git a/src/test/java/org/apache/commons/io/IOUtilsWriteTest.java 
b/src/test/java/org/apache/commons/io/IOUtilsWriteTest.java
index 5024976..1c2fdec 100644
--- a/src/test/java/org/apache/commons/io/IOUtilsWriteTest.java
+++ b/src/test/java/org/apache/commons/io/IOUtilsWriteTest.java
@@ -18,7 +18,7 @@ package org.apache.commons.io;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.fail;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.io.OutputStream;
 import java.io.OutputStreamWriter;
@@ -33,7 +33,7 @@ import 
org.apache.commons.io.test.ThrowOnFlushAndCloseOutputStream;
 import org.junit.jupiter.api.Test;
 
 /**
- * JUnit tests for IOUtils write methods.
+ * Tests IOUtils write methods.
  *
  * @see IOUtils
  */
@@ -71,11 +71,7 @@ public class IOUtilsWriteTest {
 
     @Test
     public void testWrite_byteArrayToOutputStream_nullStream() throws 
Exception {
-        try {
-            IOUtils.write(inData, (OutputStream) null);
-            fail();
-        } catch (final NullPointerException ignore) {
-        }
+        assertThrows(NullPointerException.class, () -> IOUtils.write(inData, 
(OutputStream) null));
     }
 
     @Test
@@ -140,11 +136,7 @@ public class IOUtilsWriteTest {
 
     @Test
     public void testWrite_byteArrayToWriter_Encoding_nullWriter() throws 
Exception {
-        try {
-            IOUtils.write(inData, null, "UTF8");
-            fail();
-        } catch (final NullPointerException ignore) {
-        }
+        assertThrows(NullPointerException.class, () -> IOUtils.write(inData, 
null, "UTF8"));
     }
 
     @Test
@@ -163,11 +155,7 @@ public class IOUtilsWriteTest {
 
     @Test
     public void testWrite_byteArrayToWriter_nullWriter() throws Exception {
-        try {
-            IOUtils.write(inData, (Writer) null);
-            fail();
-        } catch (final NullPointerException ignore) {
-        }
+        assertThrows(NullPointerException.class, () -> IOUtils.write(inData, 
(Writer) null));
     }
 
     @Test
@@ -216,11 +204,7 @@ public class IOUtilsWriteTest {
     @Test
     public void testWrite_charArrayToOutputStream_Encoding_nullStream() throws 
Exception {
         final String str = new String(inData, StandardCharsets.US_ASCII);
-        try {
-            IOUtils.write(str.toCharArray(), (OutputStream) null);
-            fail();
-        } catch (final NullPointerException ignore) {
-        }
+        assertThrows(NullPointerException.class, () -> 
IOUtils.write(str.toCharArray(), (OutputStream) null));
     }
 
     @Test
@@ -253,11 +237,7 @@ public class IOUtilsWriteTest {
     @Test
     public void testWrite_charArrayToOutputStream_nullStream() throws 
Exception {
         final String str = new String(inData, StandardCharsets.US_ASCII);
-        try {
-            IOUtils.write(str.toCharArray(), (OutputStream) null);
-            fail();
-        } catch (final NullPointerException ignore) {
-        }
+        assertThrows(NullPointerException.class, () -> 
IOUtils.write(str.toCharArray(), (OutputStream) null));
     }
 
     @Test
@@ -294,11 +274,7 @@ public class IOUtilsWriteTest {
     @Test
     public void testWrite_charArrayToWriter_Encoding_nullStream() throws 
Exception {
         final String str = new String(inData, StandardCharsets.US_ASCII);
-        try {
-            IOUtils.write(str.toCharArray(), (Writer) null);
-            fail();
-        } catch (final NullPointerException ignore) {
-        }
+        assertThrows(NullPointerException.class, () -> 
IOUtils.write(str.toCharArray(), (Writer) null));
     }
 
     @Test
@@ -347,11 +323,7 @@ public class IOUtilsWriteTest {
     @Test
     public void testWrite_charSequenceToOutputStream_Encoding_nullStream() 
throws Exception {
         final CharSequence csq = new StringBuilder(new String(inData, 
StandardCharsets.US_ASCII));
-        try {
-            IOUtils.write(csq, (OutputStream) null);
-            fail();
-        } catch (final NullPointerException ignore) {
-        }
+        assertThrows(NullPointerException.class, () -> IOUtils.write(csq, 
(OutputStream) null));
     }
 
     @Test
@@ -384,11 +356,7 @@ public class IOUtilsWriteTest {
     @Test
     public void testWrite_charSequenceToOutputStream_nullStream() throws 
Exception {
         final CharSequence csq = new StringBuilder(new String(inData, 
StandardCharsets.US_ASCII));
-        try {
-            IOUtils.write(csq, (OutputStream) null);
-            fail();
-        } catch (final NullPointerException ignore) {
-        }
+        assertThrows(NullPointerException.class, () -> IOUtils.write(csq, 
(OutputStream) null));
     }
 
     @Test
@@ -425,11 +393,7 @@ public class IOUtilsWriteTest {
     @Test
     public void testWrite_charSequenceToWriter_Encoding_nullStream() throws 
Exception {
         final CharSequence csq = new StringBuilder(new String(inData, 
StandardCharsets.US_ASCII));
-        try {
-            IOUtils.write(csq, (Writer) null);
-            fail();
-        } catch (final NullPointerException ignore) {
-        }
+        assertThrows(NullPointerException.class, () -> IOUtils.write(csq, 
(Writer) null));
     }
 
     @Test
@@ -478,11 +442,7 @@ public class IOUtilsWriteTest {
     @Test
     public void testWrite_stringToOutputStream_Encoding_nullStream() throws 
Exception {
         final String str = new String(inData, StandardCharsets.US_ASCII);
-        try {
-            IOUtils.write(str, (OutputStream) null);
-            fail();
-        } catch (final NullPointerException ignore) {
-        }
+        assertThrows(NullPointerException.class, () -> IOUtils.write(str, 
(OutputStream) null));
     }
 
     @Test
@@ -515,11 +475,7 @@ public class IOUtilsWriteTest {
     @Test
     public void testWrite_stringToOutputStream_nullStream() throws Exception {
         final String str = new String(inData, StandardCharsets.US_ASCII);
-        try {
-            IOUtils.write(str, (OutputStream) null);
-            fail();
-        } catch (final NullPointerException ignore) {
-        }
+        assertThrows(NullPointerException.class, () -> IOUtils.write(str, 
(OutputStream) null));
     }
 
     @Test
@@ -556,11 +512,7 @@ public class IOUtilsWriteTest {
     @Test
     public void testWrite_stringToWriter_Encoding_nullStream() throws 
Exception {
         final String str = new String(inData, StandardCharsets.US_ASCII);
-        try {
-            IOUtils.write(str, (Writer) null);
-            fail();
-        } catch (final NullPointerException ignore) {
-        }
+        assertThrows(NullPointerException.class, () -> IOUtils.write(str, 
(Writer) null));
     }
 
     @Test
@@ -653,11 +605,7 @@ public class IOUtilsWriteTest {
     public void testWriteLines_OutputStream_Encoding_nullStream() throws 
Exception {
         final Object[] data = {"hello", "world"};
         final List<Object> list = Arrays.asList(data);
-        try {
-            IOUtils.writeLines(list, "*", null, "US-ASCII");
-            fail();
-        } catch (final NullPointerException ignore) {
-        }
+        assertThrows(NullPointerException.class, () -> 
IOUtils.writeLines(list, "*", null, "US-ASCII"));
     }
 
     @Test
@@ -693,11 +641,7 @@ public class IOUtilsWriteTest {
     public void testWriteLines_OutputStream_nullStream() throws Exception {
         final Object[] data = {"hello", "world"};
         final List<Object> list = Arrays.asList(data);
-        try {
-            IOUtils.writeLines(list, "*", (OutputStream) null);
-            fail();
-        } catch (final NullPointerException ignore) {
-        }
+        assertThrows(NullPointerException.class, () -> 
IOUtils.writeLines(list, "*", (OutputStream) null));
     }
 
     @Test
@@ -758,11 +702,7 @@ public class IOUtilsWriteTest {
     public void testWriteLines_Writer_nullStream() throws Exception {
         final Object[] data = {"hello", "world"};
         final List<Object> list = Arrays.asList(data);
-        try {
-            IOUtils.writeLines(list, "*", (Writer) null);
-            fail();
-        } catch (final NullPointerException ignore) {
-        }
+        assertThrows(NullPointerException.class, () -> 
IOUtils.writeLines(list, "*", (Writer) null));
     }
 
 }
diff --git a/src/test/java/org/apache/commons/io/filefilter/FileFilterTest.java 
b/src/test/java/org/apache/commons/io/filefilter/FileFilterTest.java
index 1a84b43..2f72835 100644
--- a/src/test/java/org/apache/commons/io/filefilter/FileFilterTest.java
+++ b/src/test/java/org/apache/commons/io/filefilter/FileFilterTest.java
@@ -266,18 +266,8 @@ public class FileFilterTest extends AbstractFilterTest {
         assertFiltering(filter, testFile, false);
         assertNotNull(filter.toString()); // TODO better test
 
-        try {
-            new DelegateFileFilter((FileFilter) null);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-
-        try {
-            new DelegateFileFilter((FilenameFilter) null);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-
+        assertThrows(IllegalArgumentException.class, () -> new 
DelegateFileFilter((FileFilter) null));
+        assertThrows(IllegalArgumentException.class, () -> new 
DelegateFileFilter((FilenameFilter) null));
     }
 
     @Test
@@ -356,26 +346,9 @@ public class FileFilterTest extends AbstractFilterTest {
         assertEquals(FileVisitResult.TERMINATE, listFilter.accept(bmpPath, 
null));
         assertEquals(FileVisitResult.TERMINATE, listFilter.accept(dirPath, 
null));
 
-        try {
-            new WildcardFilter((String) null);
-            fail();
-        } catch (final IllegalArgumentException ex) {
-            // expected
-        }
-
-        try {
-            new WildcardFilter((String[]) null);
-            fail();
-        } catch (final IllegalArgumentException ex) {
-            // expected
-        }
-
-        try {
-            new WildcardFilter((List<String>) null);
-            fail();
-        } catch (final IllegalArgumentException ex) {
-            // expected
-        }
+        assertThrows(IllegalArgumentException.class, () -> new 
WildcardFilter((String) null));
+        assertThrows(IllegalArgumentException.class, () -> new 
WildcardFilter((String[]) null));
+        assertThrows(IllegalArgumentException.class, () -> new 
WildcardFilter((List<String>) null));
     }
 
     @Test
@@ -596,12 +569,7 @@ public class FileFilterTest extends AbstractFilterTest {
     public void testFilterFilesArrayNullParameters() throws Exception {
         final File fileA = TestUtils.newFile(temporaryFolder, "A");
         final File fileB = TestUtils.newFile(temporaryFolder, "B");
-        try {
-            FileFilterUtils.filter(null, fileA, fileB);
-            fail();
-        } catch (final IllegalArgumentException iae) {
-            // Test passes, exception thrown for null filter
-        }
+        assertThrows(IllegalArgumentException.class, () -> 
FileFilterUtils.filter(null, fileA, fileB));
 
         final IOFileFilter filter = FileFilterUtils.trueFileFilter();
         FileFilterUtils.filter(filter, fileA, null);
@@ -651,12 +619,7 @@ public class FileFilterTest extends AbstractFilterTest {
      */
     @Test
     public void testFilterListNullParameters() {
-        try {
-            FileFilterUtils.filterList(null, Collections.emptyList());
-            fail();
-        } catch (final IllegalArgumentException iae) {
-            // Test passes, exception thrown for null filter
-        }
+        assertThrows(IllegalArgumentException.class, () -> 
FileFilterUtils.filterList(null, Collections.emptyList()));
 
         final IOFileFilter filter = FileFilterUtils.trueFileFilter();
         try {
@@ -676,12 +639,7 @@ public class FileFilterTest extends AbstractFilterTest {
     public void testFilterPathsArrayNullParameters() throws Exception {
         final Path fileA = TestUtils.newFile(temporaryFolder, "A").toPath();
         final Path fileB = TestUtils.newFile(temporaryFolder, "B").toPath();
-        try {
-            PathUtils.filter(null, fileA, fileB);
-            fail();
-        } catch (final NullPointerException iae) {
-            // Test passes, exception thrown for null filter
-        }
+        assertThrows(NullPointerException.class, () -> PathUtils.filter(null, 
fileA, fileB));
 
         final IOFileFilter filter = FileFilterUtils.trueFileFilter();
         PathUtils.filter(filter, fileA, null);
@@ -731,19 +689,10 @@ public class FileFilterTest extends AbstractFilterTest {
      */
     @Test
     public void testFilterSetNullParameters() {
-        try {
-            FileFilterUtils.filterSet(null, Collections.emptySet());
-            fail();
-        } catch (final IllegalArgumentException iae) {
-            // Test passes, exception thrown for null filter
-        }
+        assertThrows(IllegalArgumentException.class, () -> 
FileFilterUtils.filterSet(null, Collections.emptySet()));
 
         final IOFileFilter filter = FileFilterUtils.trueFileFilter();
-        try {
-            FileFilterUtils.filterSet(filter, new 
HashSet<>(Collections.singletonList(null)));
-        } catch (final IllegalArgumentException iae) {
-            // Test passes, exception thrown for set containing null
-        }
+        FileFilterUtils.filterSet(filter, new 
HashSet<>(Collections.singletonList(null)));
 
         final Set<File> filteredSet = FileFilterUtils.filterSet(filter, 
(Set<File>) null);
         assertEquals(0, filteredSet.size());
@@ -917,42 +866,12 @@ public class FileFilterTest extends AbstractFilterTest {
 
     @Test
     public void testMagicNumberFileFilterValidation() {
-        try {
-            new MagicNumberFileFilter((String) null, 0);
-            fail();
-        } catch (final IllegalArgumentException iae) {
-            // expected
-        }
-        try {
-            new MagicNumberFileFilter("0", -1);
-            fail();
-        } catch (final IllegalArgumentException iae) {
-            // expected
-        }
-        try {
-            new MagicNumberFileFilter("", 0);
-            fail();
-        } catch (final IllegalArgumentException iae) {
-            // expected
-        }
-        try {
-            new MagicNumberFileFilter((byte[]) null, 0);
-            fail();
-        } catch (final IllegalArgumentException iae) {
-            // expected
-        }
-        try {
-            new MagicNumberFileFilter(new byte[] {0}, -1);
-            fail();
-        } catch (final IllegalArgumentException iae) {
-            // expected
-        }
-        try {
-            new MagicNumberFileFilter(new byte[] {}, 0);
-            fail();
-        } catch (final IllegalArgumentException iae) {
-            // expected
-        }
+        assertThrows(IllegalArgumentException.class, () -> new 
MagicNumberFileFilter((String) null, 0));
+        assertThrows(IllegalArgumentException.class, () -> new 
MagicNumberFileFilter("0", -1));
+        assertThrows(IllegalArgumentException.class, () -> new 
MagicNumberFileFilter("", 0));
+        assertThrows(IllegalArgumentException.class, () -> new 
MagicNumberFileFilter((byte[]) null, 0));
+        assertThrows(IllegalArgumentException.class, () -> new 
MagicNumberFileFilter(new byte[] {0}, -1));
+        assertThrows(IllegalArgumentException.class, () -> new 
MagicNumberFileFilter(new byte[] {}, 0));
     }
 
     @Test
@@ -997,7 +916,6 @@ public class FileFilterTest extends AbstractFilterTest {
         assertFiltering(filter2, file, false);
     }
 
-    // -----------------------------------------------------------------------
     @Test
     public void testMakeDirectoryOnly() throws Exception {
         assertSame(DirectoryFileFilter.DIRECTORY, 
FileFilterUtils.makeDirectoryOnly(null));
@@ -1279,23 +1197,9 @@ public class FileFilterTest extends AbstractFilterTest {
         assertEquals(FileVisitResult.TERMINATE, listFilter.accept(testPath, 
null));
         assertEquals(FileVisitResult.CONTINUE, listFilter.accept(fredPath, 
null));
 
-        try {
-            new PrefixFileFilter((String) null);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-
-        try {
-            new PrefixFileFilter((String[]) null);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-
-        try {
-            new PrefixFileFilter((List<String>) null);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
+        assertThrows(IllegalArgumentException.class, () -> new 
PrefixFileFilter((String) null));
+        assertThrows(IllegalArgumentException.class, () -> new 
PrefixFileFilter((String[]) null));
+        assertThrows(IllegalArgumentException.class, () -> new 
PrefixFileFilter((List<String>) null));
     }
 
     @Test
@@ -1320,24 +1224,9 @@ public class FileFilterTest extends AbstractFilterTest {
         assertFiltering(filter, new File("FOO.test3"), true); // case-sensitive
         assertFiltering(filter, new File("BAR.test3"), true); // case-sensitive
 
-        try {
-            new PrefixFileFilter((String) null, IOCase.INSENSITIVE);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-
-        try {
-            new PrefixFileFilter((String[]) null, IOCase.INSENSITIVE);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-
-        try {
-            new PrefixFileFilter((List<String>) null, IOCase.INSENSITIVE);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-
+        assertThrows(IllegalArgumentException.class, () -> new 
PrefixFileFilter((String) null, IOCase.INSENSITIVE));
+        assertThrows(IllegalArgumentException.class, () -> new 
PrefixFileFilter((String[]) null, IOCase.INSENSITIVE));
+        assertThrows(IllegalArgumentException.class, () -> new 
PrefixFileFilter((List<String>) null, IOCase.INSENSITIVE));
         // FileFilterUtils.prefixFileFilter(String, IOCase) tests
         filter = FileFilterUtils.prefixFileFilter("bar", IOCase.INSENSITIVE);
         assertFiltering(filter, new File("foo.test2"), false);
@@ -1345,11 +1234,7 @@ public class FileFilterTest extends AbstractFilterTest {
         assertFiltering(filter, new File("FOO.test2"), false); // 
case-sensitive
         assertFiltering(filter, new File("BAR.test2"), true); // case-sensitive
 
-        try {
-            FileFilterUtils.prefixFileFilter(null, IOCase.INSENSITIVE);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
+        assertThrows(IllegalArgumentException.class, () -> 
FileFilterUtils.prefixFileFilter(null, IOCase.INSENSITIVE));
     }
 
     @Test
@@ -1396,12 +1281,7 @@ public class FileFilterTest extends AbstractFilterTest {
         assertFiltering(filter7, largeFile, true);
         assertFiltering(filter8, largeFile, true);
 
-        try {
-            FileFilterUtils.sizeFileFilter(-1);
-            fail();
-        } catch (final IllegalArgumentException ex) {
-            // expected
-        }
+        assertThrows(IllegalArgumentException.class, () -> 
FileFilterUtils.sizeFileFilter(-1));
     }
 
     @Test
@@ -1448,12 +1328,7 @@ public class FileFilterTest extends AbstractFilterTest {
         assertFiltering(filter7, largeFile, true);
         assertFiltering(filter8, largeFile, true);
 
-        try {
-            FileFilterUtils.sizeFileFilter(-1);
-            fail();
-        } catch (final IllegalArgumentException ex) {
-            // expected
-        }
+        assertThrows(IllegalArgumentException.class, () -> 
FileFilterUtils.sizeFileFilter(-1));
     }
 
     @Test
@@ -1505,23 +1380,9 @@ public class FileFilterTest extends AbstractFilterTest {
         assertEquals(FileVisitResult.TERMINATE, listFilter.accept(testPath, 
null));
         assertEquals(FileVisitResult.CONTINUE, listFilter.accept(fredPath, 
null));
 
-        try {
-            new SuffixFileFilter((String) null);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-
-        try {
-            new SuffixFileFilter((String[]) null);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-
-        try {
-            new SuffixFileFilter((List<String>) null);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
+        assertThrows(IllegalArgumentException.class, () -> new 
SuffixFileFilter((String) null));
+        assertThrows(IllegalArgumentException.class, () -> new 
SuffixFileFilter((String[]) null));
+        assertThrows(IllegalArgumentException.class, () -> new 
SuffixFileFilter((List<String>) null));
     }
 
     @Test
@@ -1546,34 +1407,16 @@ public class FileFilterTest extends AbstractFilterTest {
         assertFiltering(filter, new File("bar.TES"), true); // case-sensitive
         assertFiltering(filter, new File("bar.exe"), false);
 
-        try {
-            new SuffixFileFilter((String) null, IOCase.INSENSITIVE);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-
-        try {
-            new SuffixFileFilter((String[]) null, IOCase.INSENSITIVE);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-
-        try {
-            new SuffixFileFilter((List<String>) null, IOCase.INSENSITIVE);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
+        assertThrows(IllegalArgumentException.class, () -> new 
SuffixFileFilter((String) null, IOCase.INSENSITIVE));
+        assertThrows(IllegalArgumentException.class, () -> new 
SuffixFileFilter((String[]) null, IOCase.INSENSITIVE));
+        assertThrows(IllegalArgumentException.class, () -> new 
SuffixFileFilter((List<String>) null, IOCase.INSENSITIVE));
 
         // FileFilterUtils.suffixFileFilter(String, IOCase) tests
         filter = FileFilterUtils.suffixFileFilter("est", IOCase.INSENSITIVE);
         assertFiltering(filter, new File("test"), true);
         assertFiltering(filter, new File("TEST"), true);
 
-        try {
-            FileFilterUtils.suffixFileFilter(null, IOCase.INSENSITIVE);
-            fail();
-        } catch (final IllegalArgumentException ex) {
-        }
+        assertThrows(IllegalArgumentException.class, () -> 
FileFilterUtils.suffixFileFilter(null, IOCase.INSENSITIVE));
     }
 
     @Test
diff --git 
a/src/test/java/org/apache/commons/io/filefilter/RegexFileFilterTest.java 
b/src/test/java/org/apache/commons/io/filefilter/RegexFileFilterTest.java
index c85bcaf..95883a4 100644
--- a/src/test/java/org/apache/commons/io/filefilter/RegexFileFilterTest.java
+++ b/src/test/java/org/apache/commons/io/filefilter/RegexFileFilterTest.java
@@ -16,6 +16,7 @@
  */
 package org.apache.commons.io.filefilter;
 
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.fail;
 
@@ -115,33 +116,10 @@ public class RegexFileFilterTest {
 
     @Test
     public void testRegexEdgeCases() {
-        try {
-            new RegexFileFilter((String) null);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-            // expected
-        }
-
-        try {
-            new RegexFileFilter(null, Pattern.CASE_INSENSITIVE);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-            // expected
-        }
-
-        try {
-            new RegexFileFilter(null, IOCase.INSENSITIVE);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-            // expected
-        }
-
-        try {
-            new RegexFileFilter((java.util.regex.Pattern) null);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-            // expected
-        }
+        assertThrows(IllegalArgumentException.class, () -> new 
RegexFileFilter((String) null));
+        assertThrows(IllegalArgumentException.class, () -> new 
RegexFileFilter(null, Pattern.CASE_INSENSITIVE));
+        assertThrows(IllegalArgumentException.class, () -> new 
RegexFileFilter(null, IOCase.INSENSITIVE));
+        assertThrows(IllegalArgumentException.class, () -> new 
RegexFileFilter((java.util.regex.Pattern) null));
     }
 
     /**
diff --git 
a/src/test/java/org/apache/commons/io/filefilter/WildcardFileFilterTest.java 
b/src/test/java/org/apache/commons/io/filefilter/WildcardFileFilterTest.java
index 426f221..74efea0 100644
--- a/src/test/java/org/apache/commons/io/filefilter/WildcardFileFilterTest.java
+++ b/src/test/java/org/apache/commons/io/filefilter/WildcardFileFilterTest.java
@@ -19,6 +19,7 @@ package org.apache.commons.io.filefilter;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
@@ -26,6 +27,7 @@ import java.io.File;
 import java.nio.file.FileVisitResult;
 import java.nio.file.Path;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 
 import org.apache.commons.io.IOCase;
@@ -141,20 +143,8 @@ public class WildcardFileFilterTest extends 
AbstractFilterTest {
         assertEquals(FileVisitResult.TERMINATE, listFilter.accept(bmpPath, 
null));
         assertEquals(FileVisitResult.TERMINATE, listFilter.accept(dirPath, 
null));
 
-        try {
-            new WildcardFileFilter((String) null);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-        try {
-            new WildcardFileFilter((String[]) null);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
-        try {
-            new WildcardFileFilter((List<String>) null);
-            fail();
-        } catch (final IllegalArgumentException ignore) {
-        }
+        assertThrows(IllegalArgumentException.class, () -> new 
WildcardFileFilter((String) null));
+        assertThrows(IllegalArgumentException.class, () -> new 
WildcardFileFilter((String[]) null));
+        assertThrows(IllegalArgumentException.class, () -> new 
WildcardFileFilter((List<String>) null));
     }
 }
diff --git 
a/src/test/java/org/apache/commons/io/output/LockableFileWriterTest.java 
b/src/test/java/org/apache/commons/io/output/LockableFileWriterTest.java
index ac4db68..cf3bdda 100644
--- a/src/test/java/org/apache/commons/io/output/LockableFileWriterTest.java
+++ b/src/test/java/org/apache/commons/io/output/LockableFileWriterTest.java
@@ -17,6 +17,7 @@
 package org.apache.commons.io.output;
 
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
@@ -25,14 +26,15 @@ import java.io.IOException;
 import java.io.Writer;
 import java.nio.charset.StandardCharsets;
 import java.nio.charset.UnsupportedCharsetException;
+import java.util.List;
 
+import org.apache.commons.io.filefilter.WildcardFileFilter;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
 /**
- * Tests that files really lock, although no writing is done as
- * the locking is tested only on construction.
+ * Tests that files really lock, although no writing is done as the locking is 
tested only on construction.
  *
  */
 public class LockableFileWriterTest {
@@ -55,19 +57,19 @@ public class LockableFileWriterTest {
         altLockFile = new File(altLockDir, file.getName() + ".lck");
     }
 
-    @Test public void testAlternateLockDir() throws IOException {
+    @Test
+    public void testAlternateLockDir() throws IOException {
         // open a valid lockable writer
-        try (LockableFileWriter lfw1 = new LockableFileWriter(file, "UTF-8" 
,true, altLockDir.getAbsolutePath())){
+        try (LockableFileWriter lfw1 = new LockableFileWriter(file, "UTF-8", 
true, altLockDir.getAbsolutePath())) {
             assertTrue(file.exists());
             assertTrue(altLockFile.exists());
 
             // try to open a second writer
-            try (LockableFileWriter lfw2 = new LockableFileWriter(file, 
StandardCharsets.UTF_8, true, altLockDir.getAbsolutePath())){
+            try (LockableFileWriter lfw2 = new LockableFileWriter(file, 
StandardCharsets.UTF_8, true, altLockDir.getAbsolutePath())) {
                 fail("Somehow able to open a locked file. ");
-            } catch(final IOException ioe) {
+            } catch (final IOException ioe) {
                 final String msg = ioe.getMessage();
-                assertTrue(msg.startsWith("Can't write file, lock "),
-                        "Exception message does not start correctly. ");
+                assertTrue(msg.startsWith("Can't write file, lock "), 
"Exception message does not start correctly. ");
                 assertTrue(file.exists());
                 assertTrue(altLockFile.exists());
             }
@@ -76,55 +78,48 @@ public class LockableFileWriterTest {
         assertFalse(altLockFile.exists());
     }
 
-    @Test public void testConstructor_File_directory() {
-        try (Writer writer = new LockableFileWriter(temporaryFolder)) {
-            fail();
-        } catch (final IOException ex) {
-            // expected
-            assertFalse(file.exists());
-            assertFalse(lockFile.exists());
-        }
+    @Test
+    public void testConstructor_File_directory() {
+        assertThrows(IOException.class, () -> new 
LockableFileWriter(temporaryFolder));
+        assertFalse(file.exists());
+        assertFalse(lockFile.exists());
+        // again
         assertFalse(file.exists());
         assertFalse(lockFile.exists());
     }
 
-    @Test public void testConstructor_File_encoding_badEncoding() throws 
IOException {
-        try (Writer writer = new LockableFileWriter(file, "BAD-ENCODE")) {
-            fail();
-        } catch (final UnsupportedCharsetException ex) {
-            // expected
-            assertFalse(file.exists());
-            assertFalse(lockFile.exists());
-        }
+    @Test
+    public void testConstructor_File_encoding_badEncoding() throws IOException 
{
+        assertThrows(UnsupportedCharsetException.class, () -> new 
LockableFileWriter(file, "BAD-ENCODE"));
+        assertFalse(file.exists());
+        assertFalse(lockFile.exists());
+        // again
         assertFalse(file.exists());
         assertFalse(lockFile.exists());
     }
 
-    @Test public void testConstructor_File_nullFile() throws IOException {
-        try (Writer writer = new LockableFileWriter((File) null)) {
-            fail();
-        } catch (final NullPointerException ex) {
-            // expected
-            assertFalse(file.exists());
-            assertFalse(lockFile.exists());
-        }
+    @Test
+    public void testConstructor_File_nullFile() throws IOException {
+        assertThrows(NullPointerException.class, () -> new 
LockableFileWriter((File) null));
+        assertFalse(file.exists());
+        assertFalse(lockFile.exists());
+        // again
         assertFalse(file.exists());
         assertFalse(lockFile.exists());
     }
 
-    @Test public void testConstructor_fileName_nullFile() throws IOException {
-        try (Writer writer = new LockableFileWriter((String) null)) {
-            fail();
-        } catch (final NullPointerException ex) {
-            // expected
-            assertFalse(file.exists());
-            assertFalse(lockFile.exists());
-        }
+    @Test
+    public void testConstructor_fileName_nullFile() throws IOException {
+        assertThrows(NullPointerException.class, () -> new 
LockableFileWriter((String) null));
+        assertFalse(file.exists());
+        assertFalse(lockFile.exists());
+        // again
         assertFalse(file.exists());
         assertFalse(lockFile.exists());
     }
 
-    @Test public void testFileLocked() throws IOException {
+    @Test
+    public void testFileLocked() throws IOException {
 
         // open a valid lockable writer
         try (LockableFileWriter lfw1 = new LockableFileWriter(file)) {
@@ -134,10 +129,9 @@ public class LockableFileWriterTest {
             // try to open a second writer
             try (LockableFileWriter lfw2 = new LockableFileWriter(file)) {
                 fail("Somehow able to open a locked file. ");
-            } catch(final IOException ioe) {
+            } catch (final IOException ioe) {
                 final String msg = ioe.getMessage();
-                assertTrue(msg.startsWith("Can't write file, lock "),
-                        "Exception message does not start correctly. ");
+                assertTrue(msg.startsWith("Can't write file, lock "), 
"Exception message does not start correctly. ");
                 assertTrue(file.exists());
                 assertTrue(lockFile.exists());
             }
@@ -145,10 +139,9 @@ public class LockableFileWriterTest {
             // try to open a third writer
             try (LockableFileWriter lfw3 = new LockableFileWriter(file)) {
                 fail("Somehow able to open a locked file. ");
-            } catch(final IOException ioe) {
+            } catch (final IOException ioe) {
                 final String msg = ioe.getMessage();
-                assertTrue(msg.startsWith("Can't write file, lock "),
-                        "Exception message does not start correctly. ");
+                assertTrue(msg.startsWith("Can't write file, lock "), 
"Exception message does not start correctly. ");
                 assertTrue(file.exists());
                 assertTrue(lockFile.exists());
             }
@@ -157,7 +150,8 @@ public class LockableFileWriterTest {
         assertFalse(lockFile.exists());
     }
 
-    @Test public void testFileNotLocked() throws IOException {
+    @Test
+    public void testFileNotLocked() throws IOException {
         // open a valid lockable writer
         try (LockableFileWriter lfw1 = new LockableFileWriter(file)) {
             assertTrue(file.exists());

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