#322 Added MatcherAssume.assumeThat again

hamcrest/hamcrest.gradle

@@ -3,6 +3,7 @@ apply plugin: 'osgi'
 version = rootProject.version
 
 dependencies {
+    api 'org.opentest4j:opentest4j:1.2.0'
     testImplementation(group: 'junit', name: 'junit', version: '4.13') {
         transitive = false
     }

hamcrest/src/main/java/org/hamcrest/MatcherAssume.java

@@ -0,0 +1,27 @@
+package org.hamcrest;
+
+import org.opentest4j.TestAbortedException;
+
+public final class MatcherAssume {
+
+    private MatcherAssume() {
+    }
+
+    public static <T> void assumeThat(T assumption, Matcher<? super T> matcher) {
+        assumeThat("", assumption, matcher);
+    }
+
+    public static <T> void assumeThat(String message, T assumption, Matcher<? super T> matcher) {
+        if (!matcher.matches(assumption)) {
+            throwTestAbortedException(message);
+        }
+    }
+
+    private static void throwTestAbortedException(String message) {
+        throw new TestAbortedException(isNotBlank(message) ? "Assumption failed: " + message : "Assumption failed");
+    }
+
+    private static boolean isNotBlank(String string) {
+        return string != null && !string.trim().isEmpty();
+    }
+}

hamcrest/src/test/java/org/hamcrest/MatcherAssumeTest.java

@@ -0,0 +1,38 @@
+package org.hamcrest;
+
+import org.junit.Test;
+import org.opentest4j.TestAbortedException;
+
+import static org.hamcrest.MatcherAssume.assumeThat;
+import static org.hamcrest.Matchers.startsWith;
+import static org.junit.Assert.*;
+
+public class MatcherAssumeTest {
+
+    @Test public void
+    assumptionFailsWithMessage() {
+        try {
+            assumeThat("Custom assumption", "a", startsWith("abc"));
+            fail("should have failed");
+        }
+        catch (TestAbortedException e) {
+            assertEquals("Assumption failed: Custom assumption", e.getMessage());
+        }
+    }
+
+    @Test public void
+    assumptionFailsWithDefaultMessage() {
+        try {
+            assumeThat("a", startsWith("abc"));
+            fail("should have failed");
+        }
+        catch (TestAbortedException e) {
+            assertEquals("Assumption failed", e.getMessage());
+        }
+    }
+
+    @Test public void
+    assumptionSucceeds() {
+        assumeThat("xyz", startsWith("xy"));
+    }
+}