jqno#199 Support empty enums

akhalikov · Jul 30, 2018 · 0f9a148 · 0f9a148
1 parent bc30b81
commit 0f9a148
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Showing 9 changed files with 54 additions and 16 deletions.
diff --git a/src/main/java/nl/jqno/equalsverifier/internal/checkers/FieldsChecker.java b/src/main/java/nl/jqno/equalsverifier/internal/checkers/FieldsChecker.java
@@ -210,7 +210,7 @@ private void assertFieldShouldBeIgnored(boolean equalToItself, boolean equalsCha
             boolean fieldIsEligible = !referenceAccessor.fieldIsStatic() &&
                     !referenceAccessor.fieldIsTransient() &&
                     !classAccessor.fieldHasAnnotation(referenceAccessor.getField(), SupportedAnnotations.TRANSIENT) &&
-                    !referenceAccessor.fieldIsSingleValueEnum();
+                    !referenceAccessor.fieldIsEmptyOrSingleValueEnum();
 
             if (allFieldsShouldBeUsed && fieldIsEligible) {
                 assertTrue(Formatter.of("Significant fields: equals does not use %%.", fieldName), equalToItself);

diff --git a/src/main/java/nl/jqno/equalsverifier/internal/prefabvalues/PrefabValues.java b/src/main/java/nl/jqno/equalsverifier/internal/prefabvalues/PrefabValues.java
@@ -127,6 +127,9 @@ public <T> T giveOther(TypeTag tag, T value) {
         }
 
         Tuple<T> tuple = giveTuple(tag);
+        if (tuple.getRed() == null) {
+            return null;
+        }
         if (type.isArray() && arraysAreDeeplyEqual(tuple.getRed(), value)) {
             return tuple.getBlack();
         }

diff --git a/src/main/java/nl/jqno/equalsverifier/internal/prefabvalues/factories/FallbackFactory.java b/src/main/java/nl/jqno/equalsverifier/internal/prefabvalues/factories/FallbackFactory.java
@@ -1,6 +1,5 @@
 package nl.jqno.equalsverifier.internal.prefabvalues.factories;
 
-import nl.jqno.equalsverifier.internal.exceptions.ReflectionException;
 import nl.jqno.equalsverifier.internal.prefabvalues.PrefabValues;
 import nl.jqno.equalsverifier.internal.prefabvalues.Tuple;
 import nl.jqno.equalsverifier.internal.prefabvalues.TypeTag;
@@ -45,7 +44,7 @@ private Tuple<T> giveEnumInstances(TypeTag tag) {
 
         switch (enumConstants.length) {
             case 0:
-                throw new ReflectionException("Enum " + type.getSimpleName() + " has no elements");
+                return new Tuple<>(null, null, null);
             case 1:
                 return new Tuple<>(enumConstants[0], enumConstants[0], enumConstants[0]);
             default:

diff --git a/src/main/java/nl/jqno/equalsverifier/internal/reflection/FieldAccessor.java b/src/main/java/nl/jqno/equalsverifier/internal/reflection/FieldAccessor.java
@@ -85,9 +85,9 @@ public boolean fieldIsTransient() {
     /**
      * Returns whether the field is an enum with a single value.
      */
-    public boolean fieldIsSingleValueEnum() {
+    public boolean fieldIsEmptyOrSingleValueEnum() {
         Class<?> type = field.getType();
-        return type.isEnum() && type.getEnumConstants().length == 1;
+        return type.isEnum() && type.getEnumConstants().length <= 1;
     }
 
     /**

diff --git a/src/test/java/nl/jqno/equalsverifier/integration/extended_contract/EnumTest.java b/src/test/java/nl/jqno/equalsverifier/integration/extended_contract/EnumTest.java
@@ -17,6 +17,12 @@ public void succeed_whenClassIsAnEnum() {
                 .verify();
     }
 
+    @Test
+    public void succeed_whenClassHasAnEmptyEnumButIgnoresIt() {
+        EqualsVerifier.forClass(EmptyEnumContainer.class)
+                .verify();
+    }
+
     @Test
     public void succeed_whenClassHasASingletonEnumButIgnoresIt() {
         EqualsVerifier.forClass(SingletonContainer.class)
@@ -54,6 +60,31 @@ enum Enum {
 
     enum Singleton { INSTANCE }
 
+    enum Empty {}
+
+    static final class EmptyEnumContainer {
+        private final int i;
+
+        @SuppressWarnings("unused")
+        private final Empty empty;
+
+        public EmptyEnumContainer(int i, Empty empty) { this.i = i; this.empty = empty; }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (!(obj instanceof EmptyEnumContainer)) {
+                return false;
+            }
+            EmptyEnumContainer other = (EmptyEnumContainer)obj;
+            return i == other.i;
+        }
+
+        @Override
+        public int hashCode() {
+            return i;
+        }
+    }
+
     static final class SingletonContainer {
         private final int i;
 

diff --git a/src/test/java/nl/jqno/equalsverifier/internal/prefabvalues/PrefabValuesCreatorTest.java b/src/test/java/nl/jqno/equalsverifier/internal/prefabvalues/PrefabValuesCreatorTest.java
@@ -1,7 +1,6 @@
 package nl.jqno.equalsverifier.internal.prefabvalues;
 
 import nl.jqno.equalsverifier.internal.exceptions.RecursionException;
-import nl.jqno.equalsverifier.internal.exceptions.ReflectionException;
 import nl.jqno.equalsverifier.testhelpers.PrefabValuesFactory;
 import nl.jqno.equalsverifier.testhelpers.types.Point;
 import nl.jqno.equalsverifier.testhelpers.types.RecursiveTypeHelper.*;
@@ -21,6 +20,7 @@ public class PrefabValuesCreatorTest {
     private static final TypeTag POINT_TAG = new TypeTag(Point.class);
     private static final TypeTag ENUM_TAG = new TypeTag(Enum.class);
     private static final TypeTag ONE_ELT_ENUM_TAG = new TypeTag(OneElementEnum.class);
+    private static final TypeTag EMPTY_ENUM_TAG = new TypeTag(EmptyEnum.class);
     private static final TypeTag NODE_TAG = new TypeTag(Node.class);
     private static final TypeTag NODE_ARRAY_TAG = new TypeTag(NodeArray.class);
     private static final TypeTag TWOSTEP_NODE_A_TAG = new TypeTag(TwoStepNodeA.class);
@@ -66,9 +66,8 @@ public void createOneElementEnum() {
 
     @Test
     public void createEmptyEnum() {
-        thrown.expect(ReflectionException.class);
-        thrown.expectMessage("Enum EmptyEnum has no elements");
-        prefabValues.giveRed(new TypeTag(EmptyEnum.class));
+        assertNull(prefabValues.giveRed(EMPTY_ENUM_TAG));
+        assertNull(prefabValues.giveBlack(EMPTY_ENUM_TAG));
     }
 
     @Test

diff --git a/...test/java/nl/jqno/equalsverifier/internal/prefabvalues/factories/FallbackFactoryTest.java b/...test/java/nl/jqno/equalsverifier/internal/prefabvalues/factories/FallbackFactoryTest.java
@@ -1,7 +1,6 @@
 package nl.jqno.equalsverifier.internal.prefabvalues.factories;
 
 import nl.jqno.equalsverifier.internal.exceptions.RecursionException;
-import nl.jqno.equalsverifier.internal.exceptions.ReflectionException;
 import nl.jqno.equalsverifier.internal.prefabvalues.PrefabValues;
 import nl.jqno.equalsverifier.internal.prefabvalues.Tuple;
 import nl.jqno.equalsverifier.internal.prefabvalues.TypeTag;
@@ -42,9 +41,8 @@ public void setUp() {
     }
 
     @Test
-    public void dontGiveEmptyEnum() {
-        thrown.expect(ReflectionException.class);
-        new FallbackFactory<>().createValues(new TypeTag(EmptyEnum.class), prefabValues, typeStack);
+    public void giveNullInsteadOfEmptyEnum() {
+        assertCorrectTuple(EmptyEnum.class, null, null);
     }
 
     @Test

diff --git a/src/test/java/nl/jqno/equalsverifier/internal/reflection/FieldAccessorTest.java b/src/test/java/nl/jqno/equalsverifier/internal/reflection/FieldAccessorTest.java
@@ -117,21 +117,28 @@ public void isTransient() {
     public void isNotEnum() {
         PrimitiveContainer foo = new PrimitiveContainer();
         FieldAccessor fieldAccessor = getAccessorFor(foo, FIELD_NAME);
-        assertFalse(fieldAccessor.fieldIsSingleValueEnum());
+        assertFalse(fieldAccessor.fieldIsEmptyOrSingleValueEnum());
     }
 
     @Test
     public void isEnumButNotSingleValue() {
         EnumContainer foo = new EnumContainer();
         FieldAccessor fieldAccessor = getAccessorFor(foo, "twoElementEnum");
-        assertFalse(fieldAccessor.fieldIsSingleValueEnum());
+        assertFalse(fieldAccessor.fieldIsEmptyOrSingleValueEnum());
     }
 
     @Test
     public void isSingleValueEnum() {
         EnumContainer foo = new EnumContainer();
         FieldAccessor fieldAccessor = getAccessorFor(foo, "oneElementEnum");
-        assertTrue(fieldAccessor.fieldIsSingleValueEnum());
+        assertTrue(fieldAccessor.fieldIsEmptyOrSingleValueEnum());
+    }
+
+    @Test
+    public void isEmptyEnum() {
+        EnumContainer foo = new EnumContainer();
+        FieldAccessor fieldAccessor = getAccessorFor(foo, "emptyEnum");
+        assertTrue(fieldAccessor.fieldIsEmptyOrSingleValueEnum());
     }
 
     @Test

diff --git a/src/test/java/nl/jqno/equalsverifier/testhelpers/types/TypeHelper.java b/src/test/java/nl/jqno/equalsverifier/testhelpers/types/TypeHelper.java
@@ -244,6 +244,7 @@ public enum EmptyEnum {}
 
     @SuppressWarnings("unused")
     public static final class EnumContainer {
+        private EmptyEnum emptyEnum;
         private OneElementEnum oneElementEnum;
         private TwoElementEnum twoElementEnum;
     }