[commons-numbers] 03/03: Test abs() and arg() return the input to ofPolar constructor.

[aherbert]

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

commit ceb62698d95a6b6a562a896c8ed8e82e72f1e411
Author: Alex Herbert <aherb...@apache.org>
AuthorDate: Sat Dec 21 17:16:29 2019 +0000

    Test abs() and arg() return the input to ofPolar constructor.
---
 .../org/apache/commons/numbers/complex/ComplexTest.java   | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git 
a/commons-numbers-complex/src/test/java/org/apache/commons/numbers/complex/ComplexTest.java
 
b/commons-numbers-complex/src/test/java/org/apache/commons/numbers/complex/ComplexTest.java
index 7d6770d..82c2cee 100644
--- 
a/commons-numbers-complex/src/test/java/org/apache/commons/numbers/complex/ComplexTest.java
+++ 
b/commons-numbers-complex/src/test/java/org/apache/commons/numbers/complex/ComplexTest.java
@@ -123,6 +123,21 @@ public class ComplexTest {
     }
 
     @Test
+    public void testPolarConstructorAbsArg() {
+        // The test should work with any seed but use a fixed seed to avoid 
build instability.
+        final UniformRandomProvider rng = 
RandomSource.create(RandomSource.SPLIT_MIX_64, 678678638L);
+        for (int i = 0; i < 10; i++) {
+            final double rho = rng.nextDouble();
+            // Range (pi, pi]: lower exclusive, upper inclusive
+            final double theta = pi - rng.nextDouble() * 2 * pi;
+            final Complex z = Complex.ofPolar(rho, theta);
+            // Match within 1 ULP
+            Assertions.assertEquals(rho, z.abs(), Math.ulp(rho));
+            Assertions.assertEquals(theta, z.arg(), Math.ulp(theta));
+        }
+    }
+
+    @Test
     public void testCisConstructor() {
         final double x = 0.12345;
         final Complex z = Complex.ofCis(x);