Merge pull request #658 from pimterry/iterable-datapoints

Added support for iterable datapoints

src/main/java/org/junit/experimental/theories/DataPoints.java

@@ -8,9 +8,9 @@
 import java.lang.annotation.Target;
 
 /**
- * Annotating an array-typed field or method with @DataPoints will cause
- * the values in the array (or returned array) to be used as potential
- * parameters for theories in that class, when run with the
+ * Annotating an array or iterable-typed field or method with @DataPoints
+ * will cause the values in the array or iterable given to be used as potential
+ * parameters for theories in that class when run with the
  * {@link org.junit.experimental.theories.Theories Theories} runner.
  * <p>
  * DataPoints will only be considered as potential values for parameters for
@@ -27,6 +27,14 @@
  * &#064;ParameterSuppliedBy} annotations) will use all DataPoints that are
  * assignable to the parameter type as potential values, including named sets of
  * DataPoints.
+ * <p>
+ * DataPoints methods whose array types aren't assignable from the target
+ * parameter type (and so can't possibly return relevant values) will not be
+ * called when generating values for that parameter. Iterable-typed datapoints
+ * methods must always be called though, as this information is not available
+ * here after generic type erasure, so expensive methods returning iterable
+ * datapoints are a bad idea.
+ * 
  * <pre>
  * &#064;DataPoints
  * public static String[] dataPoints = new String[] { ... };
@@ -48,8 +56,9 @@
  * @see org.junit.experimental.theories.FromDataPoints
  */
 @Retention(RetentionPolicy.RUNTIME)
-@Target({FIELD, METHOD})
+@Target({ FIELD, METHOD })
 public @interface DataPoints {
     String[] value() default {};
+
     Class<? extends Throwable>[] ignoredExceptions() default {};
 }

src/main/java/org/junit/experimental/theories/internal/AllMembersSupplier.java

@@ -4,6 +4,7 @@
 import java.lang.reflect.Field;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Iterator;
 import java.util.List;
 
 import org.junit.Assume;
@@ -76,9 +77,11 @@ private void addMultiPointMethods(ParameterSignature sig, List<PotentialAssignme
         for (FrameworkMethod dataPointsMethod : getDataPointsMethods(sig)) {
             Class<?> returnType = dataPointsMethod.getReturnType();
 
-            if (returnType.isArray() && sig.canPotentiallyAcceptType(returnType.getComponentType())) {
+            if ((returnType.isArray() && sig.canPotentiallyAcceptType(returnType.getComponentType())) ||
+                    Iterable.class.isAssignableFrom(returnType)) {
                 try {
-                    addArrayValues(sig, dataPointsMethod.getName(), list, dataPointsMethod.invokeExplosively(null));
+                    addDataPointsValues(returnType, sig, dataPointsMethod.getName(), list, 
+                            dataPointsMethod.invokeExplosively(null));
                 } catch (Throwable throwable) {
                     DataPoints annotation = dataPointsMethod.getAnnotation(DataPoints.class);
                     if (annotation != null && isAssignableToAnyOf(annotation.ignoredExceptions(), throwable)) {
@@ -101,9 +104,10 @@ private void addSinglePointMethods(ParameterSignature sig, List<PotentialAssignm
 
     private void addMultiPointFields(ParameterSignature sig, List<PotentialAssignment> list) {
         for (final Field field : getDataPointsFields(sig)) {
-            addArrayValues(sig, field.getName(), list, getStaticFieldValue(field));
+            Class<?> type = field.getType();
+            addDataPointsValues(type, sig, field.getName(), list, getStaticFieldValue(field));
         }
-    }    
+    }
 
     private void addSinglePointFields(ParameterSignature sig, List<PotentialAssignment> list) {
         for (final Field field : getSingleDataPointFields(sig)) {
@@ -114,6 +118,16 @@ private void addSinglePointFields(ParameterSignature sig, List<PotentialAssignme
             }
         }
     }
+
+    private void addDataPointsValues(Class<?> type, ParameterSignature sig, String name, 
+            List<PotentialAssignment> list, Object value) {
+        if (type.isArray()) {
+            addArrayValues(sig, name, list, value);
+        }
+        else if (Iterable.class.isAssignableFrom(type)) {
+            addIterableValues(sig, name, list, (Iterable<?>) value);
+        }
+    }
 
     private void addArrayValues(ParameterSignature sig, String name, List<PotentialAssignment> list, Object array) {
         for (int i = 0; i < Array.getLength(array); i++) {
@@ -123,6 +137,18 @@ private void addArrayValues(ParameterSignature sig, String name, List<PotentialA
             }
         }
     }
+
+    private void addIterableValues(ParameterSignature sig, String name, List<PotentialAssignment> list, Iterable<?> iterable) {
+        Iterator<?> iterator = iterable.iterator();
+        int i = 0;
+        while (iterator.hasNext()) {
+            Object value = iterator.next();
+            if (sig.canAcceptValue(value)) {
+                list.add(PotentialAssignment.forValue(name + "[" + i + "]", value));
+            }
+            i += 1;
+        }
+    }
 
     private Object getStaticFieldValue(final Field field) {
         try {

src/test/java/org/junit/tests/experimental/theories/internal/AllMembersSupplierTest.java

@@ -6,6 +6,7 @@
 import static org.junit.Assert.assertThat;
 import static org.junit.tests.experimental.theories.TheoryTestUtils.potentialAssignments;
 
+import java.util.Arrays;
 import java.util.List;
 
 import org.junit.Rule;
@@ -23,7 +24,6 @@ public class AllMembersSupplierTest {
     @Rule
     public ExpectedException expected = ExpectedException.none();
 
-
     public static class HasDataPointsArrayField {
         @DataPoints
         public static String[] list = new String[] { "qwe", "asd" };
@@ -153,4 +153,57 @@ private List<PotentialAssignment> allMemberValuesFor(Class<?> testClass,
                         testClass.getConstructor(constructorParameterTypes))
                         .get(0));
     }
-}
+
+    public static class HasDataPointsListField {
+        @DataPoints
+        public static List<String> list = Arrays.asList("one", "two");
+
+        @Theory
+        public void theory(String param) {
+        }
+    }
+
+    @Test
+    public void dataPointsCollectionFieldsShouldBeRecognized() throws Throwable {
+        List<PotentialAssignment> assignments = potentialAssignments(
+            HasDataPointsListField.class.getMethod("theory", String.class));
+
+        assertEquals(2, assignments.size());
+    }
+
+    public static class HasDataPointsListMethod {
+        @DataPoints
+        public static List<String> getList() {
+            return Arrays.asList("one", "two");
+        }
+
+        @Theory
+        public void theory(String param) {
+        }
+    }
+
+    @Test
+    public void dataPointsCollectionMethodShouldBeRecognized() throws Throwable {
+        List<PotentialAssignment> assignments = potentialAssignments(
+            HasDataPointsListMethod.class.getMethod("theory", String.class));
+
+        assertEquals(2, assignments.size());
+    }
+
+    public static class HasDataPointsListFieldWithOverlyGenericTypes {
+        @DataPoints
+        public static List<Object> list = Arrays.asList("string", new Object());
+
+        @Theory
+        public void theory(String param) {
+        }
+    }
+
+    @Test
+    public void dataPointsCollectionShouldBeRecognizedIgnoringStrangeTypes() throws Throwable {
+        List<PotentialAssignment> assignments = potentialAssignments(
+            HasDataPointsListFieldWithOverlyGenericTypes.class.getMethod("theory", String.class));
+
+        assertEquals(1, assignments.size());
+    }
+}