Add IOComparator

2 files changed, 83 insertions, 8 deletions

diff --git a/src/test/java/org/apache/commons/io/function/IOComparatorTest.java b/src/test/java/org/apache/commons/io/function/IOComparatorTest.java
new file mode 100644
index 00000000..b263f5d1
--- /dev/null
+++ b/src/test/java/org/apache/commons/io/function/IOComparatorTest.java
@@ -0,0 +1,63 @@
+/*
+ * 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.io.function;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests {@link IOComparator}.
+ */
+public class IOComparatorTest {
+
+    /** {@link Files#size(Path)} throws IOException */
+    static final IOComparator<Path> PATH_SIZE_COMP = (final Path t, final Path u) -> Long.compare(Files.size(t), Files.size(u));
+
+    /** {@link Path#toRealPath(java.nio.file.LinkOption...)} throws IOException */
+    static final IOComparator<Path> REAL_PATH_COMP = (final Path t, final Path u) -> t.toRealPath().compareTo(u);
+
+    @Test
+    public void testAsComparator() throws IOException {
+        assertEquals(0, REAL_PATH_COMP.asComparator().compare(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_A));
+        assertThrows(UncheckedIOException.class,
+            () -> TestConstants.THROWING_IO_COMPARATOR.asComparator().compare(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_B));
+    }
+
+    @Test
+    public void testCompareLong() throws IOException {
+        assertEquals(0, REAL_PATH_COMP.compare(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_A));
+    }
+
+    @Test
+    public void testComparePath() throws IOException {
+        assertEquals(0, PATH_SIZE_COMP.compare(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_A));
+    }
+
+    @Test
+    public void testThrowing() throws IOException {
+        assertThrows(IOException.class, () -> TestConstants.THROWING_IO_COMPARATOR.compare(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_B));
+    }
+
+}
diff --git a/src/test/java/org/apache/commons/io/function/TestConstants.java b/src/test/java/org/apache/commons/io/function/TestConstants.java
index 545e71e3..c361e878 100644
--- a/src/test/java/org/apache/commons/io/function/TestConstants.java
+++ b/src/test/java/org/apache/commons/io/function/TestConstants.java
@@ -19,6 +19,8 @@ package org.apache.commons.io.function;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.function.Predicate;
 
 /**
@@ -26,27 +28,33 @@ import java.util.function.Predicate;
  */
 class TestConstants {
 
-    static IOConsumer<Object> THROWING_IO_CONSUMER = t -> {
+    static final Path ABS_PATH_A = Paths.get("LICENSE.txt").toAbsolutePath();
+
+    static final Path ABS_PATH_B = Paths.get("NOTICE.txt").toAbsolutePath();
+
+    static IOBiConsumer<Object, Object> THROWING_IO_BI_CONSUMER = (t, u) -> {
         throw new IOException("Failure");
     };
 
-    static IOFunction<Object, Object> THROWING_IO_FUNCTION = t -> {
+    static IOBiFunction<Object, Object, Object> THROWING_IO_BI_FUNCTION = (t, u) -> {
         throw new IOException("Failure");
     };
 
-    static IOBiFunction<Object, Object, Object> THROWING_IO_BI_FUNCTION = (t, u) -> {
+    static IOComparator<Object> THROWING_IO_COMPARATOR = (t, u) -> throwIOException();
+
+    static IOConsumer<Object> THROWING_IO_CONSUMER = t -> {
         throw new IOException("Failure");
     };
 
-    static IOTriFunction<Object, Object, Object, Object> THROWING_IO_TRI_FUNCTION = (t, u, v) -> {
+    static IOFunction<Object, Object> THROWING_IO_FUNCTION = t -> {
         throw new IOException("Failure");
     };
 
-    static IOQuadFunction<Object, Object, Object, Object, Object> THROWING_IO_QUAD_FUNCTION = (t, u, v, w) -> {
+    static IOPredicate<Object> THROWING_IO_PREDICATE = t -> {
         throw new IOException("Failure");
     };
 
-    static IOSupplier<Object> THROWING_IO_SUPPLIER = () -> {
+    static IOQuadFunction<Object, Object, Object, Object, Object> THROWING_IO_QUAD_FUNCTION = (t, u, v, w) -> {
         throw new IOException("Failure");
     };
 
@@ -54,7 +62,7 @@ class TestConstants {
         throw new IOException("Failure");
     };
 
-    static IOBiConsumer<Object, Object> THROWING_IO_BI_CONSUMER = (t, u) -> {
+    static IOSupplier<Object> THROWING_IO_SUPPLIER = () -> {
         throw new IOException("Failure");
     };
 
@@ -62,7 +70,7 @@ class TestConstants {
         throw new IOException("Failure");
     };
 
-    static IOPredicate<Object> THROWING_IO_PREDICATE = t -> {
+    static IOTriFunction<Object, Object, Object, Object> THROWING_IO_TRI_FUNCTION = (t, u, v) -> {
         throw new IOException("Failure");
     };
 
@@ -70,4 +78,8 @@ class TestConstants {
         throw new UncheckedIOException(new IOException("Failure"));
     };
 
+    private static <T> T throwIOException() throws IOException {
+        throw new IOException("Failure");
+    }
+
 }