1 files changed, 141 insertions, 0 deletions
diff --git a/src/test/java/org/apache/commons/lang3/stream/LangCollectorsTest.java b/src/test/java/org/apache/commons/lang3/stream/LangCollectorsTest.java
new file mode 100644
index 000000000..e8f408498
--- /dev/null
+++ b/src/test/java/org/apache/commons/lang3/stream/LangCollectorsTest.java
@@ -0,0 +1,141 @@
+/*
+ * 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.stream;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.Function;
+import java.util.stream.Collector;
+import java.util.stream.Stream;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests {@link LangCollectors}
+ */
+public class LangCollectorsTest {
+
+    private static class Fixture {
+        int value;
+
+        private Fixture(final int value) {
+            this.value = value;
+        }
+
+        @Override
+        public String toString() {
+            return Integer.toString(value);
+        }
+    }
+
+    private static final Long _1L = Long.valueOf(1);
+    private static final Long _2L = Long.valueOf(2);
+    private static final Long _3L = Long.valueOf(3);
+
+    private static final Function<Object, String> TO_STRING = Objects::toString;
+
+    private static final Collector<Object, ?, String> JOINING_0 = LangCollectors.joining();
+    private static final Collector<Object, ?, String> JOINING_1 = LangCollectors.joining("-");
+    private static final Collector<Object, ?, String> JOINING_3 = LangCollectors.joining("-", "<", ">");
+    private static final Collector<Object, ?, String> JOINING_4 = LangCollectors.joining("-", "<", ">", TO_STRING);
+    private static final Collector<Object, ?, String> JOINING_4_NUL = LangCollectors.joining("-", "<", ">", o -> Objects.toString(o, "NUL"));
+
+    @Test
+    public void testJoiningNonStrings0Arg() {
+        assertEquals("", Stream.of().collect(JOINING_0));
+        assertEquals("1", Stream.of(_1L).collect(JOINING_0));
+        assertEquals("12", Stream.of(_1L, _2L).collect(JOINING_0));
+        assertEquals("123", Stream.of(_1L, _2L, _3L).collect(JOINING_0));
+        assertEquals("1null3", Stream.of(_1L, null, _3L).collect(JOINING_0));
+        assertEquals("12", Stream.of(new AtomicLong(1), new AtomicLong(2)).collect(JOINING_0));
+        assertEquals("12", Stream.of(new Fixture(1), new Fixture(2)).collect(JOINING_0));
+    }
+
+    @Test
+    public void testJoiningNonStrings1Arg() {
+        assertEquals("", Stream.of().collect(JOINING_1));
+        assertEquals("1", Stream.of(_1L).collect(JOINING_1));
+        assertEquals("1-2", Stream.of(_1L, _2L).collect(JOINING_1));
+        assertEquals("1-2-3", Stream.of(_1L, _2L, _3L).collect(JOINING_1));
+        assertEquals("1-null-3", Stream.of(_1L, null, _3L).collect(JOINING_1));
+        assertEquals("1-2", Stream.of(new AtomicLong(1), new AtomicLong(2)).collect(JOINING_1));
+        assertEquals("1-2", Stream.of(new Fixture(1), new Fixture(2)).collect(JOINING_1));
+    }
+
+    @Test
+    public void testJoiningNonStrings3Args() {
+        assertEquals("<>", Stream.of().collect(JOINING_3));
+        assertEquals("<1>", Stream.of(_1L).collect(JOINING_3));
+        assertEquals("<1-2>", Stream.of(_1L, _2L).collect(JOINING_3));
+        assertEquals("<1-2-3>", Stream.of(_1L, _2L, _3L).collect(JOINING_3));
+        assertEquals("<1-null-3>", Stream.of(_1L, null, _3L).collect(JOINING_3));
+        assertEquals("<1-2>", Stream.of(new AtomicLong(1), new AtomicLong(2)).collect(JOINING_3));
+        assertEquals("<1-2>", Stream.of(new Fixture(1), new Fixture(2)).collect(JOINING_3));
+    }
+
+    @Test
+    public void testJoiningNonStrings4Args() {
+        assertEquals("<>", Stream.of().collect(JOINING_4));
+        assertEquals("<1>", Stream.of(_1L).collect(JOINING_4));
+        assertEquals("<1-2>", Stream.of(_1L, _2L).collect(JOINING_4));
+        assertEquals("<1-2-3>", Stream.of(_1L, _2L, _3L).collect(JOINING_4));
+        assertEquals("<1-null-3>", Stream.of(_1L, null, _3L).collect(JOINING_4));
+        assertEquals("<1-NUL-3>", Stream.of(_1L, null, _3L).collect(JOINING_4_NUL));
+        assertEquals("<1-2>", Stream.of(new AtomicLong(1), new AtomicLong(2)).collect(JOINING_4));
+        assertEquals("<1-2>", Stream.of(new Fixture(1), new Fixture(2)).collect(JOINING_4));
+    }
+
+    @Test
+    public void testJoiningStrings0Arg() {
+        assertEquals("", Stream.of().collect(JOINING_0));
+        assertEquals("1", Stream.of("1").collect(JOINING_0));
+        assertEquals("12", Stream.of("1", "2").collect(JOINING_0));
+        assertEquals("123", Stream.of("1", "2", "3").collect(JOINING_0));
+        assertEquals("1null3", Stream.of("1", null, "3").collect(JOINING_0));
+    }
+
+    @Test
+    public void testJoiningStrings1Arg() {
+        assertEquals("", Stream.of().collect(JOINING_1));
+        assertEquals("1", Stream.of("1").collect(JOINING_1));
+        assertEquals("1-2", Stream.of("1", "2").collect(JOINING_1));
+        assertEquals("1-2-3", Stream.of("1", "2", "3").collect(JOINING_1));
+        assertEquals("1-null-3", Stream.of("1", null, "3").collect(JOINING_1));
+    }
+
+    @Test
+    public void testJoiningStrings3Args() {
+        assertEquals("<>", Stream.of().collect(JOINING_3));
+        assertEquals("<1>", Stream.of("1").collect(JOINING_3));
+        assertEquals("<1-2>", Stream.of("1", "2").collect(JOINING_3));
+        assertEquals("<1-2-3>", Stream.of("1", "2", "3").collect(JOINING_3));
+        assertEquals("<1-null-3>", Stream.of("1", null, "3").collect(JOINING_3));
+    }
+
+    @Test
+    public void testJoiningStrings4Args() {
+        assertEquals("<>", Stream.of().collect(JOINING_4));
+        assertEquals("<1>", Stream.of("1").collect(JOINING_4));
+        assertEquals("<1-2>", Stream.of("1", "2").collect(JOINING_4));
+        assertEquals("<1-2-3>", Stream.of("1", "2", "3").collect(JOINING_4));
+        assertEquals("<1-null-3>", Stream.of("1", null, "3").collect(JOINING_4));
+        assertEquals("<1-NUL-3>", Stream.of("1", null, "3").collect(JOINING_4_NUL));
+    }
+}