1 files changed, 101 insertions, 0 deletions
diff --git a/src/test/java/org/apache/commons/lang3/function/MethodInvokersFunctionTest.java b/src/test/java/org/apache/commons/lang3/function/MethodInvokersFunctionTest.java
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+++ b/src/test/java/org/apache/commons/lang3/function/MethodInvokersFunctionTest.java
@@ -0,0 +1,101 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.lang3.function;
+
+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 java.lang.reflect.Method;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import org.apache.commons.lang3.exception.CustomUncheckedException;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests {@link MethodInvokers#asFunction(Method)}.
+ */
+public class MethodInvokersFunctionTest extends MethodFixtures {
+
+    @Test
+    public void testApply0Arg() throws NoSuchMethodException, SecurityException {
+        final Function<MethodFixtures, String> func = MethodInvokers.asFunction(getMethodForGetString());
+        assertEquals(INSTANCE.getString(), func.apply(INSTANCE));
+    }
+
+    @Test
+    public void testApply0ArgThrowsUnchecked() throws NoSuchMethodException, SecurityException {
+        final Function<MethodFixtures, String> func = MethodInvokers.asFunction(getMethodForGetStringThrowsUnchecked());
+        assertThrows(CustomUncheckedException.class, () -> func.apply(INSTANCE));
+    }
+
+    @Test
+    public void testBuildVarArg() throws SecurityException, NoSuchMethodException {
+        MethodInvokers.asFunction(getMethodForGetStringVarStringArgs());
+    }
+
+    @Test
+    public void testConstructorForNull() throws SecurityException {
+        assertThrows(NullPointerException.class, () -> MethodInvokers.asFunction(null));
+    }
+
+    @Test
+    public void testFindAndInvoke() throws SecurityException {
+        // Finding
+        final List<Function<Object, Object>> invokers = Stream.of(MethodFixtures.class.getDeclaredMethods())
+            .filter(m -> m.isAnnotationPresent(AnnotationTestFixture.class)).map(MethodInvokers::asFunction).collect(Collectors.toList());
+        assertEquals(2, invokers.size());
+        // ...
+        // Invoking
+        final Set<Object> set1 = invokers.stream().map(i -> i.apply(MethodFixtures.INSTANCE)).collect(Collectors.toSet());
+        assertEquals(new HashSet<>(Arrays.asList(INSTANCE.getString(), INSTANCE.getString2())), set1);
+        final Set<Object> set2 = Stream.of(INSTANCE).map(invokers.get(0)).collect(Collectors.toSet());
+        final Set<Object> set3 = Stream.of(INSTANCE).map(invokers.get(1)).collect(Collectors.toSet());
+        set2.addAll(set3);
+        assertEquals(new HashSet<>(Arrays.asList(INSTANCE.getString(), INSTANCE.getString2())), set2);
+    }
+
+    @Test
+    public void testFullExample() throws SecurityException, ReflectiveOperationException {
+        final Method method = String.class.getMethod("length");
+        final Function<String, Integer> function = MethodInvokers.asFunction(method);
+        assertEquals(3, function.apply("ABC"));
+    }
+
+    @Test
+    public void testMapComputeIfAbsent() throws NoSuchMethodException, SecurityException {
+        final Map<MethodFixtures, String> map = new HashMap<>();
+        map.computeIfAbsent(INSTANCE, MethodInvokers.asFunction(getMethodForGetString()));
+        assertEquals(INSTANCE.getString(), map.get(INSTANCE));
+    }
+
+    @Test
+    public void testToString() throws SecurityException, ReflectiveOperationException {
+        // Should not blow up and must return _something_
+        assertFalse(MethodInvokers.asFunction(getMethodForGetString()).toString().isEmpty());
+    }
+
+}