https://github.com/hamcrest/JavaHamcrest/issues/8

Fixed mismatch reporting on isCloseTo()
martiner · Aug 28, 2012 · 46b5ec0 · 46b5ec0
1 parent 749ef4b
commit 46b5ec0
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Showing 5 changed files with 72 additions and 60 deletions.
diff --git a/hamcrest-library/src/main/java/org/hamcrest/number/BigDecimalCloseTo.java b/hamcrest-library/src/main/java/org/hamcrest/number/BigDecimalCloseTo.java
@@ -1,13 +1,13 @@
 package org.hamcrest.number;
 
-import java.math.BigDecimal;
-import java.math.MathContext;
-
 import org.hamcrest.Description;
 import org.hamcrest.Factory;
 import org.hamcrest.Matcher;
 import org.hamcrest.TypeSafeMatcher;
 
+import java.math.BigDecimal;
+import java.math.MathContext;
+
 public class BigDecimalCloseTo extends TypeSafeMatcher<BigDecimal> {
 
   private final BigDecimal delta;
@@ -27,7 +27,9 @@ public boolean matchesSafely(BigDecimal item) {
   public void describeMismatchSafely(BigDecimal item, Description mismatchDescription) {
       mismatchDescription.appendValue(item)
               .appendText(" differed by ")
-              .appendValue(actualDelta(item));
+              .appendValue(actualDelta(item))
+              .appendText(" more than delta ")
+              .appendValue(delta);
   }
 
   @Override

diff --git a/hamcrest-library/src/main/java/org/hamcrest/number/IsCloseTo.java b/hamcrest-library/src/main/java/org/hamcrest/number/IsCloseTo.java
@@ -3,10 +3,12 @@
 package org.hamcrest.number;
 
 import org.hamcrest.Description;
-import org.hamcrest.Matcher;
 import org.hamcrest.Factory;
+import org.hamcrest.Matcher;
 import org.hamcrest.TypeSafeMatcher;
 
+import static java.lang.Math.abs;
+
 
 /**
  * Is the value a number equal to a value within some range of
@@ -30,7 +32,9 @@ public boolean matchesSafely(Double item) {
     public void describeMismatchSafely(Double item, Description mismatchDescription) {
       mismatchDescription.appendValue(item)
                          .appendText(" differed by ")
-                         .appendValue(actualDelta(item));
+                         .appendValue(actualDelta(item))
+                         .appendText(" more than delta ")
+                         .appendValue(delta);
     }
 
     @Override
@@ -42,7 +46,7 @@ public void describeTo(Description description) {
     }
 
     private double actualDelta(Double item) {
-      return (Math.abs((item - value)) - delta);
+      return abs(item - value) - delta;
     }
 
     /**

diff --git a/hamcrest-unit-test/src/main/java/org/hamcrest/AbstractMatcherTest.java b/hamcrest-unit-test/src/main/java/org/hamcrest/AbstractMatcherTest.java
@@ -7,43 +7,49 @@
 
 public abstract class AbstractMatcherTest extends TestCase {
 
-    /**
-     * Create an instance of the Matcher so some generic safety-net tests can be run on it.
-     */
-    protected abstract Matcher<?> createMatcher();
-
-    public static <T> void assertMatches(String message, Matcher<? super T> c, T arg) {
-        Assert.assertTrue(message, c.matches(arg));
-    }
-
-    public static <T> void assertDoesNotMatch(String message, Matcher<? super T> c, T arg) {
-        Assert.assertFalse(message, c.matches(arg));
-    }
-
-    public static void assertDescription(String expected, Matcher<?> matcher) {
-        Description description = new StringDescription();
-        description.appendDescriptionOf(matcher);
-        Assert.assertEquals("Expected description", expected, description.toString().trim());
-    }
-
-    public static <T> void assertMismatchDescription(String expected, Matcher<? super T> matcher, T arg) {
-        Assert.assertFalse("Precondtion: Matcher should not match item.", matcher.matches(arg));
-        Description description = new StringDescription();
-        matcher.describeMismatch(arg, description);
-        Assert.assertEquals("Expected mismatch description", expected, description.toString().trim());
-    }
-
-    public void testIsNullSafe() {
-       // should not throw a NullPointerException
-       createMatcher().matches(null);
-    }
-
-    public void testCopesWithUnknownTypes() {
-        // should not throw ClassCastException
-        createMatcher().matches(new UnknownType());
-    }
-
-    public static class UnknownType {
+  /**
+   * Create an instance of the Matcher so some generic safety-net tests can be run on it.
+   */
+  protected abstract Matcher<?> createMatcher();
+
+  public static <T> void assertMatches(String message, Matcher<? super T> matcher, T arg) {
+    if (!matcher.matches(arg)) {
+      Assert.fail(message + " because: '" + mismatchDescription(matcher, arg) + "'");
     }
+  }
+
+  public static <T> void assertDoesNotMatch(String message, Matcher<? super T> c, T arg) {
+    Assert.assertFalse(message, c.matches(arg));
+  }
+
+  public static void assertDescription(String expected, Matcher<?> matcher) {
+    Description description = new StringDescription();
+    description.appendDescriptionOf(matcher);
+    Assert.assertEquals("Expected description", expected, description.toString().trim());
+  }
+
+  public static <T> void assertMismatchDescription(String expected, Matcher<? super T> matcher, T arg) {
+    Assert.assertFalse("Precondtion: Matcher should not match item.", matcher.matches(arg));
+    Assert.assertEquals("Expected mismatch description", expected, mismatchDescription(matcher, arg));
+  }
+
+  private static <T> String mismatchDescription(Matcher<? super T> matcher, T arg) {
+    Description description = new StringDescription();
+    matcher.describeMismatch(arg, description);
+    return description.toString().trim();
+  }
+
+  public void testIsNullSafe() {
+    // should not throw a NullPointerException
+    createMatcher().matches(null);
+  }
+
+  public void testCopesWithUnknownTypes() {
+    // should not throw ClassCastException
+    createMatcher().matches(new UnknownType());
+  }
+
+  public static class UnknownType {
+  }
 
 }
diff --git a/hamcrest-unit-test/src/main/java/org/hamcrest/number/BigDecimalCloseToTest.java b/hamcrest-unit-test/src/main/java/org/hamcrest/number/BigDecimalCloseToTest.java
@@ -1,11 +1,11 @@
 package org.hamcrest.number;
 
-import static org.hamcrest.number.BigDecimalCloseTo.closeTo;
+import org.hamcrest.AbstractMatcherTest;
+import org.hamcrest.Matcher;
 
 import java.math.BigDecimal;
 
-import org.hamcrest.AbstractMatcherTest;
-import org.hamcrest.Matcher;
+import static org.hamcrest.number.BigDecimalCloseTo.closeTo;
 
 public class BigDecimalCloseToTest  extends AbstractMatcherTest {
 
@@ -23,9 +23,9 @@ public void testEvaluatesToTrueIfArgumentIsEqualToABigDecimalWithinSomeError() {
     assertTrue(p.matches(new BigDecimal("1.5")));
 
     assertDoesNotMatch("too large", p, new BigDecimal("2.0"));
-    assertMismatchDescription("<2.0> differed by <0.5>", p, new BigDecimal("2.0"));
+    assertMismatchDescription("<2.0> differed by <0.5> more than delta <0.5>", p, new BigDecimal("2.0"));
     assertDoesNotMatch("number too small", p, new BigDecimal("0.0"));
-    assertMismatchDescription("<0.0> differed by <0.5>", p, new BigDecimal("0.0"));
+    assertMismatchDescription("<0.0> differed by <0.5> more than delta <0.5>", p, new BigDecimal("0.0"));
   }
 
   public void testEvaluatesToTrueIfArgumentHasDifferentScale() {
@@ -36,9 +36,9 @@ public void testEvaluatesToTrueIfArgumentHasDifferentScale() {
     assertTrue(p.matches(new BigDecimal("1.500000")));
 
     assertDoesNotMatch("too large", p, new BigDecimal("2.000000"));
-    assertMismatchDescription("<2.000000> differed by <0.5>", p, new BigDecimal("2.000000"));
+    assertMismatchDescription("<2.000000> differed by <0.5> more than delta <0.5>", p, new BigDecimal("2.000000"));
     assertDoesNotMatch("number too small", p, new BigDecimal("0.000000"));
-    assertMismatchDescription("<0.000000> differed by <0.5>", p, new BigDecimal("0.000000"));
+    assertMismatchDescription("<0.000000> differed by <0.5> more than delta <0.5>", p, new BigDecimal("0.000000"));
   }
 
 }
diff --git a/hamcrest-unit-test/src/main/java/org/hamcrest/number/IsCloseToTest.java b/hamcrest-unit-test/src/main/java/org/hamcrest/number/IsCloseToTest.java
@@ -4,27 +4,27 @@
 
 import org.hamcrest.AbstractMatcherTest;
 import org.hamcrest.Matcher;
+
 import static org.hamcrest.number.IsCloseTo.closeTo;
 
 public class IsCloseToTest extends AbstractMatcherTest {
 
     @Override
     protected Matcher<?> createMatcher() {
-        double irrelevant = 0.1;
+        final double irrelevant = 0.1;
         return closeTo(irrelevant, irrelevant);
     }
 
-    public void testEvaluatesToTrueIfArgumentIsEqualToADoubleValueWithinSomeError() {
-        Matcher<Double> p = closeTo(1.0, 0.5);
+    public void test_matchesIfArgumentIsEqualToADoubleValueWithinSomeError() {
+        final Matcher<Double> p = closeTo(1.0d, 0.5d);
 
-        assertTrue(p.matches(1.0));
-        assertTrue(p.matches(0.5d));
-        assertTrue(p.matches(1.5d));
+        assertMatches("1.0", p, 1.0);
+        assertMatches("0.5d", p, 0.5d);
+        assertMatches("1.5d", p, 1.5d);
 
         assertDoesNotMatch("too large", p, 2.0);
-        assertMismatchDescription("<2.0> differed by <0.5>", p, 2.0);
+        assertMismatchDescription("<3.0> differed by <1.5> more than delta <0.5>", p, 3.0d);
         assertDoesNotMatch("number too small", p, 0.0);
-        assertMismatchDescription("<0.0> differed by <0.5>", p, 0.0);
+        assertMismatchDescription("<0.1> differed by <0.4> more than delta <0.5>", p, 0.1);
     }
-
 }