Merge pull request #386 from matthewfarwell/sortwith

SortMethodsWith allows the user to choose the order of execution of the methods within a test class

src/main/java/org/junit/FixMethodOrder.java

@@ -0,0 +1,41 @@
+package org.junit;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.junit.runners.MethodSorters;
+
+/**
+ * This class allows the user to choose the order of execution of the methods within a test class.
+ * <br/>
+ * <br/>
+ * The default order of execution of JUnit tests within a class is deterministic but not predictable.
+ * The order of execution is not guaranteed for Java 7 (and some previous versions), and can even change
+ * from run to run, so the order of execution was changed to be deterministic (in JUnit 4.11)
+ * <br/>
+ * It is recommended that test methods be written so that they are independent of the order that they are executed.
+ * However, there may be a number of dependent tests either through error or by design.
+ * This class allows the user to specify the order of execution of test methods.
+ * <br/>
+ * For possibilities, see {@link MethodSorters}
+ *
+ * Here is an example:
+ * 
+ * <pre>
+ * &#064;FixMethodOrder(MethodSorters.NAME_ASCENDING)
+ * public class MyTest {
+ * }
+ * </pre>
+ * 
+ * @see org.junit.runners.MethodSorters
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.TYPE})
+public @interface FixMethodOrder {
+	/**
+	 * Optionally specify <code>value</code> to have the methods executed in a particular order
+	 */
+	MethodSorters value() default MethodSorters.DEFAULT;
+}

src/main/java/org/junit/internal/MethodSorter.java

@@ -4,32 +4,64 @@
 import java.util.Arrays;
 import java.util.Comparator;
 
+import org.junit.FixMethodOrder;
+
 public class MethodSorter {
+    /**
+     * DEFAULT sort order
+     */
+    public static Comparator<Method> DEFAULT= new Comparator<Method>() {
+        public int compare(Method m1, Method m2) {
+            int i1 = m1.getName().hashCode();
+            int i2 = m2.getName().hashCode();
+            return i1 != i2 ? i1 - i2 : MethodSorter.compare(m1.toString(), m2.toString());
+        }
+    };
+
+    /**
+     * Method name ascending lexicograhic sort order
+     */
+    public static Comparator<Method> NAME_ASCENDING= new Comparator<Method>() {
+        public int compare(Method m1, Method m2) {
+            return MethodSorter.compare(m1.getName(), m2.getName());
+        }
+    };
 
+    private static int compare(String s1, String s2) {
+        return s1.compareTo(s2);
+    }
+
     /**
-     * Gets declared methods of a class in a predictable order.
+     * Gets declared methods of a class in a predictable order, unless @FixMethodOrder(MethodSorters.JVM) is specified.
+     * 
      * Using the JVM order is unwise since the Java platform does not
      * specify any particular order, and in fact JDK 7 returns a more or less
      * random order; well-written test code would not assume any order, but some
      * does, and a predictable failure is better than a random failure on
-     * certain platforms. Uses an unspecified but deterministic order.
+     * certain platforms. By default, uses an unspecified but deterministic order.
      * @param clazz a class
      * @return same as {@link Class#getDeclaredMethods} but sorted
      * @see <a href="http://bugs.sun.com/view_bug.do?bug_id=7023180">JDK
      *       (non-)bug #7023180</a>
      */
     public static Method[] getDeclaredMethods(Class<?> clazz) {
-        Method[] methods = clazz.getDeclaredMethods();
-        Arrays.sort(methods, new Comparator<Method>() {
-            @Override public int compare(Method m1, Method m2) {
-                int i1 = m1.getName().hashCode();
-                int i2 = m2.getName().hashCode();
-                return i1 != i2 ? i1 - i2 : m1.toString().compareTo(m2.toString());
-            }
-        });
+        Comparator<Method> comparator= getSorter(clazz.getAnnotation(FixMethodOrder.class));
+
+        Method[] methods= clazz.getDeclaredMethods();
+        if (comparator != null) {
+            Arrays.sort(methods, comparator);
+        }
+
         return methods;
     }
 
     private MethodSorter() {}
 
+    private static Comparator<Method> getSorter(FixMethodOrder fixMethodOrder) {
+        if (fixMethodOrder == null) {
+            return DEFAULT;
+        }
+
+        return fixMethodOrder.value().getComparator();
+    }
 }

src/main/java/org/junit/runners/MethodSorters.java

@@ -0,0 +1,29 @@
+package org.junit.runners;
+
+import java.lang.reflect.Method;
+import java.util.Comparator;
+
+import org.junit.internal.MethodSorter;
+
+/**
+ * Sort the methods into a specified execution order.
+ * Defines common {@link MethodSorter} implementations.
+ */
+public enum MethodSorters {
+    /** Sorts the test methods by the method name, in lexicographic order */
+    NAME_ASCENDING(MethodSorter.NAME_ASCENDING),
+    /** Sorts the test methods by the method name, in reverse lexicographic order */
+    JVM(null),
+    /** the default value, deterministic, but not predictable */
+    DEFAULT(MethodSorter.DEFAULT);
+
+    private final Comparator<Method> fComparator;
+
+    private MethodSorters(Comparator<Method> comparator) {
+        this.fComparator= comparator;
+    }
+
+    public Comparator<Method> getComparator() {
+        return fComparator;
+    }
+}

src/test/java/org/junit/internal/MethodSorterTest.java

@@ -1,34 +1,95 @@
 package org.junit.internal;
 
+import java.lang.reflect.Method;
 import java.util.Arrays;
+
+import org.junit.FixMethodOrder;
 import org.junit.Test;
+import org.junit.runners.MethodSorters;
 import static org.junit.Assert.*;
 
 public class MethodSorterTest {
+    private static final String ALPHA= "java.lang.Object alpha(int,double,java.lang.Thread)";
+    private static final String BETA= "void beta(int[][])";
+    private static final String GAMMA_VOID= "int gamma()";
+    private static final String GAMMA_BOOLEAN= "void gamma(boolean)";
+    private static final String DELTA= "void delta()";
+    private static final String EPSILON= "void epsilon()";
+
+    private static class Dummy {
+        Object alpha(int i, double d, Thread t) {return null;}
+        void beta(int[][] x) {}
+        int gamma() {return 0;}
+        void gamma(boolean b) {}
+        void delta() {}
+        void epsilon() {}
+    }
+    private static class Super {
+        void testOne() {}
+    }
+    private static class Sub extends Super {
+        void testTwo() {}
+    }
+
+    private String toString(Class<?> clazz, Method[] methods) {
+        return Arrays.toString(methods).replace(clazz.getName() + '.', "");
+    }
+
+    private String declaredMethods(Class<?> clazz) {
+        return toString(clazz, MethodSorter.getDeclaredMethods(clazz));
+    }
 
-    @Test public void getDeclaredMethods() throws Exception {
-        assertEquals("[void epsilon(), void beta(int[][]), java.lang.Object alpha(int,double,java.lang.Thread), void delta(), int gamma(), void gamma(boolean)]", declaredMethods(Dummy.class));
+    @Test public void getMethodsNullSorter() throws Exception {
+        String[] expected= new String[] { EPSILON, BETA, ALPHA, DELTA, GAMMA_VOID, GAMMA_BOOLEAN };
+        assertEquals(Arrays.asList(expected).toString(), declaredMethods(Dummy.class));
         assertEquals("[void testOne()]", declaredMethods(Super.class));
         assertEquals("[void testTwo()]", declaredMethods(Sub.class));
     }
-
-    private static String declaredMethods(Class<?> c) {
-        return Arrays.toString(MethodSorter.getDeclaredMethods(c)).replace(c.getName() + '.', "");
+
+    @FixMethodOrder(MethodSorters.DEFAULT)
+    private static class DummySortWithDefault {
+        Object alpha(int i, double d, Thread t) {return null;}
+        void beta(int[][] x) {}
+        int gamma() {return 0;}
+        void gamma(boolean b) {}
+        void delta() {}
+        void epsilon() {}
     }
 
-    private static class Dummy {
+    @Test public void testDefaultSorter() {
+        String[] expected= new String[] { EPSILON, BETA, ALPHA, DELTA, GAMMA_VOID, GAMMA_BOOLEAN };
+        assertEquals(Arrays.asList(expected).toString(), declaredMethods(DummySortWithDefault.class));
+    }
+
+    @FixMethodOrder(MethodSorters.JVM)
+    private static class DummySortJvm {
         Object alpha(int i, double d, Thread t) {return null;}
         void beta(int[][] x) {}
         int gamma() {return 0;}
         void gamma(boolean b) {}
         void delta() {}
         void epsilon() {}
     }
-    private static class Super {
-        void testOne() {}
+
+    @Test public void testSortWithJvm() {
+        Class<?> clazz= DummySortJvm.class;
+        String actual= toString(clazz, clazz.getDeclaredMethods());
+
+        assertEquals(actual, declaredMethods(clazz));
     }
-    private static class Sub extends Super {
-        void testTwo() {}
+
+    @FixMethodOrder(MethodSorters.NAME_ASCENDING)
+    private static class DummySortWithNameAsc {
+        Object alpha(int i, double d, Thread t) {return null;}
+        void beta(int[][] x) {}
+        int gamma() {return 0;}
+        void gamma(boolean b) {}
+        void delta() {}
+        void epsilon() {}
     }
 
+    @Test public void testNameAsc() {
+        String[] expected= new String[] { ALPHA, BETA, DELTA, EPSILON, GAMMA_VOID, GAMMA_BOOLEAN };
+        assertEquals(Arrays.asList(expected).toString(), declaredMethods(DummySortWithNameAsc.class));
+    }
 }

src/test/java/org/junit/tests/AllTests.java

@@ -2,6 +2,7 @@
 
 import junit.framework.JUnit4TestAdapter;
 import junit.framework.Test;
+import org.junit.internal.MethodSorterTest;
 import org.junit.runner.RunWith;
 import org.junit.runners.Suite;
 import org.junit.runners.Suite.SuiteClasses;
@@ -158,7 +159,8 @@
 	BlockJUnit4ClassRunnerOverrideTest.class,
 	RuleFieldValidatorTest.class,
 	RuleChainTest.class,
-	BlockJUnit4ClassRunnerTest.class
+	BlockJUnit4ClassRunnerTest.class,
+	MethodSorterTest.class
 })
 public class AllTests {
 	public static Test suite() {