[SDK-4366] Update to JUnit 5 (#546)

Author: jimmyjames

build.gradle

@@ -60,11 +60,13 @@ test {
         events "skipped", "failed"
         exceptionFormat "short"
     }
+    useJUnitPlatform()
 }
 
 ext {
     okhttpVersion = '4.10.0'
     hamcrestVersion = '2.2'
+    jupiterVersion = '5.9.3'
 }
 
 dependencies {
@@ -77,9 +79,9 @@ dependencies {
     testImplementation "org.bouncycastle:bcprov-jdk15on:1.68"
     testImplementation "org.mockito:mockito-core:4.8.1"
     testImplementation "com.squareup.okhttp3:mockwebserver:${okhttpVersion}"
-    testImplementation "org.hamcrest:hamcrest-core:${hamcrestVersion}"
-    testImplementation "org.hamcrest:hamcrest-library:${hamcrestVersion}"
-    testImplementation "junit:junit:4.13.1"
+    testImplementation "org.hamcrest:hamcrest:${hamcrestVersion}"
+    testImplementation "org.junit.jupiter:junit-jupiter-api:${jupiterVersion}"
+    testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:${jupiterVersion}"
 }
 
 // Creates a version.txt file containing the current version of the SDK.

src/test/java/com/auth0/AssertsUtil.java

@@ -0,0 +1,20 @@
+package com.auth0;
+
+import org.junit.jupiter.api.function.Executable;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+public class AssertsUtil {
+
+    public static <T extends Throwable> T verifyThrows(Class<T> expectedType, Executable executable) {
+        return assertThrows(expectedType, executable);
+    }
+
+    public static <T extends Throwable> T verifyThrows(Class<T> expectedType, Executable executable, String message) {
+        T result = assertThrows(expectedType, executable);
+        assertThat(result.getMessage(), is(message));
+        return result;
+    }
+}

src/test/java/com/auth0/client/HttpOptionsTest.java

@@ -1,10 +1,10 @@
 package com.auth0.client;
 
-import org.junit.Test;
-import static org.junit.Assert.assertThrows;
+import org.junit.jupiter.api.Test;
 
+import static com.auth0.AssertsUtil.verifyThrows;
 import static org.hamcrest.MatcherAssert.assertThat;
-import static org.hamcrest.Matchers.*;
+import static org.hamcrest.Matchers.is;
 
 @SuppressWarnings("deprecation")
 public class HttpOptionsTest {
@@ -44,29 +44,28 @@ public void readTimeoutMustNotBeNegative() {
     @Test
     public void apiMaxRetriesNotLessThan0() {
         HttpOptions opts = new HttpOptions();
-        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> opts.setManagementAPIMaxRetries(-1));
-        assertThat(exception.getMessage(), is("Retries must be between zero and ten."));
+        verifyThrows(IllegalArgumentException.class,
+            () -> opts.setManagementAPIMaxRetries(-1),
+            "Retries must be between zero and ten.");
     }
 
     @Test
     public void apiMaxRetriesNotGreaterThan10() {
         HttpOptions opts = new HttpOptions();
-        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> opts.setManagementAPIMaxRetries(11));
-        assertThat(exception.getMessage(), is("Retries must be between zero and ten."));
+        verifyThrows(IllegalArgumentException.class,
+            () -> opts.setManagementAPIMaxRetries(11),
+            "Retries must be between zero and ten.");
     }
 
     @Test
     public void maxRequestsMustBePositive() {
         HttpOptions opts = new HttpOptions();
-        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> opts.setMaxRequests(0));
-        assertThat(exception.getMessage(), is("maxRequests must be one or greater."));
+        verifyThrows(IllegalArgumentException.class, () -> opts.setMaxRequests(0), "maxRequests must be one or greater.");
     }
 
     @Test
     public void maxRequestsPerHostMustBePositive() {
         HttpOptions opts = new HttpOptions();
-        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> opts.setMaxRequestsPerHost(0));
-        assertThat(exception.getMessage(), is("maxRequestsPerHost must be one or greater."));
     }
 
     @Test