(#106) Introduces Mismatches Matcher to test Matchers

src/main/java/org/llorllale/cactoos/matchers/Mismatches.java

@@ -0,0 +1,148 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) for portions of project cactoos-matchers are held by
+ * Yegor Bugayenko, 2017-2018, as part of project cactoos.
+ * All other copyright for project cactoos-matchers are held by
+ * George Aristy, 2018.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package org.llorllale.cactoos.matchers;
+
+import org.cactoos.Text;
+import org.cactoos.text.Joined;
+import org.cactoos.text.TextOf;
+import org.cactoos.text.UncheckedText;
+import org.hamcrest.Description;
+import org.hamcrest.Matcher;
+import org.hamcrest.TypeSafeDiagnosingMatcher;
+
+/**
+ * Matcher to test {@link org.hamcrest.Matcher} objects.
+ *
+ * <p>Here is an example:</p>
+ * <pre>{@code
+ *  new Assertion<>(
+ *      "Can't describe a mismatch",
+ *      new HasLines("Tom", "Mike"),
+ *      new Mismatches<>(
+ *          String.format("Tom%nJohn%n"),
+ *          "Lines are <[Tom, Mike]>",
+ *          "<[Tom, John]>"
+ *      )
+ *  ).affirm();
+ *  }</pre>
+ *
+ * @param <X> Type of item.
+ * @since 1.0.0
+ * @todo #106:30min Convert all the Matcher tests to use Mismatches
+ *  instead of checking directly the output of mismatch methods or
+ *  the exception of Assertion.
+ * @todo #106:30min Add extra tests for this class to validate all
+ *  the different constructors (also add a constructor taking message
+ *  as a String) and ensure they are coherent with how Assertion is
+ *  working and throwing errors.
+ * @checkstyle ProtectedMethodInFinalClassCheck (200 lines)
+ */
+public final class Mismatches<X> extends TypeSafeDiagnosingMatcher<Matcher<X>> {
+
+    /**
+     * The testing arguments for the target matcher.
+     */
+    private final X args;
+
+    /**
+     * The expected mismatch message.
+     */
+    private final Text message;
+
+    /**
+     * Ctor.
+     * @param args The testing arguments for the matcher.
+     * @param expected The expected portion of the mismatch message.
+     * @param actual The actual portion of the mismatch message.
+     */
+    public Mismatches(
+        final X args,
+        final String expected,
+        final String actual
+    ) {
+        this(args, new TextOf(expected), new TextOf(actual));
+    }
+
+    /**
+     * Ctor.
+     * @param args The testing arguments for the matcher.
+     * @param expected The expected portion of the mismatch message.
+     * @param actual The actual portion of the mismatch message.
+     */
+    public Mismatches(
+        final X args,
+        final Text expected,
+        final Text actual
+    ) {
+        this(
+            args,
+            new Joined(
+                new TextOf("\n"),
+                new TextOf(""),
+                new Joined(new TextOf(""), new TextOf("Expected: "), expected),
+                new Joined(new TextOf(""), new TextOf(" but was: "), actual)
+            )
+        );
+    }
+
+    /**
+     * Ctor.
+     * @param args The testing arguments for the matcher.
+     * @param message The expected mismatch message.
+     */
+    public Mismatches(final X args, final Text message) {
+        super();
+        this.args = args;
+        this.message = message;
+    }
+
+    @Override
+    public void describeTo(final Description desc) {
+        desc.appendText("Mismatches ")
+            .appendValue(this.args)
+            .appendText(" with message ")
+            .appendValue(this.message);
+    }
+
+    // @todo #106:30min Add a description in case the mismatch fails.
+    //  And then introduce some tests to validate that the description
+    //  is properly constructed.
+    @Override
+    protected boolean matchesSafely(final Matcher<X> matcher,
+        final Description dsc) {
+        boolean mismatch;
+        try {
+            new Assertion<>("", this.args, matcher).affirm();
+            mismatch = false;
+        } catch (final AssertionError err) {
+            mismatch = err.getMessage().equals(
+                new UncheckedText(this.message).asString()
+            );
+        }
+        return mismatch;
+    }
+}

src/test/java/org/llorllale/cactoos/matchers/HasLinesTest.java

@@ -27,6 +27,7 @@
 
 package org.llorllale.cactoos.matchers;
 
+import org.cactoos.text.Joined;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
@@ -63,16 +64,18 @@ public void matches() {
      */
     @Test
     public void failed() {
-        this.exception.expect(AssertionError.class);
-        this.exception.expectMessage(
-            String.format(
-                "Expected: Lines are <[Tom, Mike]>%n but was: <[Tom, John]>"
-            )
-        );
         new Assertion<>(
-            "does not match lines that do not contain the given strings",
-            String.format("Tom%nJohn%n"),
-            new HasLines("Tom", "Mike")
+            "must not match lines that do not contain the given strings",
+            new HasLines("Tom", "Mike"),
+            new Mismatches<>(
+                String.format("Tom%nJohn%n"),
+                new Joined(
+                    "\n",
+                    "",
+                    "Expected: Lines are <[Tom, Mike]>",
+                    " but was: <[Tom, John]>"
+                )
+            )
         ).affirm();
     }
 

src/test/java/org/llorllale/cactoos/matchers/MismatchesTest.java

@@ -0,0 +1,69 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) for portions of project cactoos-matchers are held by
+ * Yegor Bugayenko, 2017-2018, as part of project cactoos.
+ * All other copyright for project cactoos-matchers are held by
+ * George Aristy, 2018.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.llorllale.cactoos.matchers;
+
+import org.cactoos.text.TextOf;
+import org.junit.Test;
+
+/**
+ * Test case for {@link Mismatches}.
+ *
+ * @since 1.0.0
+ * @checkstyle JavadocMethodCheck (500 lines)
+ */
+public final class MismatchesTest {
+
+    /**
+     * Example of {@link Mismatches} usage.
+     */
+    @Test
+    public void mismatches() {
+        new Assertion<>(
+            "Must mismatch properly",
+            new TextIs("abc"),
+            new Mismatches<>(
+                new TextOf("def"),
+                "Text with value \"abc\"",
+                "Text is \"def\""
+            )
+        ).affirm();
+    }
+
+    @Test
+    public void matches() {
+        new Assertion<>(
+            "Must fail to mismatch",
+            new Mismatches<>(new TextOf("a"), new TextOf("expected")),
+            new Mismatches<>(
+                new TextIs("a"),
+                "Mismatches <a> with message <expected>",
+                ""
+           )
+        ).affirm();
+    }
+}