initial classes

src/main/java/com/pholser/junit/parameters/AbstractJDKSourceOfRandomness.java

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+package com.pholser.junit.parameters;
+
+import java.util.Random;
+
+public abstract class AbstractJDKSourceOfRandomness implements SourceOfRandomness {
+    private final Random random;
+
+    protected AbstractJDKSourceOfRandomness(Random random) {
+        this.random = random;
+    }
+
+    @Override
+    public boolean nextBoolean() {
+        return random.nextBoolean();
+    }
+
+    @Override
+    public void nextBytes(byte[] bytes) {
+        random.nextBytes(bytes);
+    }
+
+    @Override
+    public byte[] nextBytes(int length) {
+        byte[] bytes = new byte[length];
+        nextBytes(bytes);
+        return bytes;
+    }
+
+    @Override
+    public double nextDouble() {
+        return random.nextDouble();
+    }
+
+    @Override
+    public float nextFloat() {
+        return random.nextFloat();
+    }
+
+    @Override
+    public double nextGaussian() {
+        return random.nextGaussian();
+    }
+
+    @Override
+    public int nextInt() {
+        return random.nextInt();
+    }
+
+    @Override
+    public int nextInt(int n) {
+        return random.nextInt(n);
+    }
+
+    @Override
+    public long nextLong() {
+        return random.nextLong();
+    }
+
+    @Override
+    public void setSeed(long seed) {
+        random.setSeed(seed);
+    }
+}

src/main/java/com/pholser/junit/parameters/ExtractedBy.java

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+package com.pholser.junit.parameters;
+
+import static java.lang.annotation.ElementType.*;
+import static java.lang.annotation.RetentionPolicy.*;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+@Target(PARAMETER)
+@Retention(RUNTIME)
+public @interface ExtractedBy {
+    Class<? extends RandomValueExtractor> value();
+}

src/main/java/com/pholser/junit/parameters/ForAll.java

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+package com.pholser.junit.parameters;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import static java.lang.annotation.ElementType.*;
+import static java.lang.annotation.RetentionPolicy.*;
+
+import org.junit.experimental.theories.ParametersSuppliedBy;
+
+@Target(PARAMETER)
+@Retention(RUNTIME)
+@ParametersSuppliedBy(GeneratingParameterSupplier.class)
+public @interface ForAll {
+    int sampleSize() default 100;
+}

src/main/java/com/pholser/junit/parameters/GeneratingParameterSupplier.java

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+package com.pholser.junit.parameters;
+
+import java.io.UnsupportedEncodingException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.junit.experimental.theories.ParameterSignature;
+import org.junit.experimental.theories.ParameterSupplier;
+import org.junit.experimental.theories.PotentialAssignment;
+
+public class GeneratingParameterSupplier extends ParameterSupplier {
+    private static final Map<Class<?>, RandomValueExtractor> extractors =
+        new HashMap<Class<?>, RandomValueExtractor>();
+
+    static {
+        extractors.put(int.class, new RandomValueExtractor() {
+            @Override
+            public Object randomValue(SourceOfRandomness random) {
+                return random.nextInt();
+            }
+        });
+        extractors.put(Integer.class, extractors.get(int.class));
+        extractors.put(double.class, new RandomValueExtractor() {
+            @Override
+            public Object randomValue(SourceOfRandomness random) {
+                return random.nextDouble();
+            }
+        });
+        extractors.put(Double.class, extractors.get(double.class));
+        extractors.put(String.class, new RandomValueExtractor() {
+            @Override
+            public Object randomValue(SourceOfRandomness random) {
+                try {
+                    return new String(random.nextBytes(16), "US-ASCII");
+                } catch (UnsupportedEncodingException ex) {
+                    throw new AssertionError(ex);
+                }
+            }
+        });
+    }
+
+    private final SourceOfRandomness random;
+
+    public GeneratingParameterSupplier() {
+        this(new SecureJDKSourceOfRandomness());
+    }
+
+    public GeneratingParameterSupplier(SourceOfRandomness random) {
+        this.random = random;
+    }
+
+    @Override
+    public List<PotentialAssignment> getValueSources(ParameterSignature sig) {
+        List<PotentialAssignment> potentials = new ArrayList<PotentialAssignment>();
+        ForAll generationParms = sig.getAnnotation(ForAll.class);
+        RandomValueExtractor extractor = extractor(sig);
+
+        for (int i = 0; i < generationParms.sampleSize(); ++i) {
+            Object generated = extractor.randomValue(random);
+            potentials.add(PotentialAssignment.forValue(String.valueOf(generated), generated));
+        }
+        return potentials;
+    }
+
+    private RandomValueExtractor extractor(ParameterSignature sig) {
+        ExtractedBy extractedBy = sig.getAnnotation(ExtractedBy.class);
+
+        if (extractedBy != null)
+            return instantiate(extractedBy.value());
+        return extractors.get(sig.getType());
+    }
+
+    private RandomValueExtractor instantiate(Class<? extends RandomValueExtractor> type) {
+        try {
+            return type.newInstance();
+        } catch (InstantiationException ex) {
+            throw new IllegalStateException(ex);
+        } catch (IllegalAccessException ex) {
+            throw new IllegalStateException(ex);
+        }
+    }
+}

src/main/java/com/pholser/junit/parameters/JDKSourceOfRandomness.java

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+package com.pholser.junit.parameters;
+
+import java.util.Random;
+
+public class JDKSourceOfRandomness extends AbstractJDKSourceOfRandomness {
+    public JDKSourceOfRandomness() {
+        super(new Random());
+    }
+}

src/main/java/com/pholser/junit/parameters/RandomValueExtractor.java

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+package com.pholser.junit.parameters;
+
+interface RandomValueExtractor {
+    Object randomValue(SourceOfRandomness random);
+}

src/main/java/com/pholser/junit/parameters/SecureJDKSourceOfRandomness.java

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+package com.pholser.junit.parameters;
+
+import java.security.SecureRandom;
+
+public class SecureJDKSourceOfRandomness extends AbstractJDKSourceOfRandomness {
+    public SecureJDKSourceOfRandomness() {
+        super(new SecureRandom());
+    }
+
+    public SecureJDKSourceOfRandomness(byte[] seed) {
+        super(new SecureRandom(seed));
+    }
+}

src/main/java/com/pholser/junit/parameters/SourceOfRandomness.java

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+package com.pholser.junit.parameters;
+
+public interface SourceOfRandomness {
+    boolean nextBoolean();
+
+    void nextBytes(byte[] bytes);
+
+    byte[] nextBytes(int length);
+
+    double nextDouble();
+
+    float nextFloat();
+
+    double nextGaussian();
+
+    int nextInt();
+
+    int nextInt(int n);
+
+    long nextLong();
+
+    void setSeed(long seed);
+}

src/test/java/com/pholser/junit/parameters/WhenMarkingTheoryParametersAsForAll.java

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+package com.pholser.junit.parameters;
+
+import static org.junit.Assert.*;
+
+import java.util.Date;
+
+import org.junit.Test;
+import org.junit.experimental.theories.Theories;
+import org.junit.experimental.theories.Theory;
+import org.junit.runner.JUnitCore;
+import org.junit.runner.RunWith;
+
+public class WhenMarkingTheoryParametersAsForAll {
+    @Test
+    public void shouldFeedDefaultNumberOfRandomIntsToAMarkedIntParameter() throws Exception {
+        JUnitCore.runClasses(ForDefaultNumberOfInts.class);
+
+        assertEquals(ForAll.class.getMethod("sampleSize").getDefaultValue(), ForDefaultNumberOfInts.iterations);
+    }
+
+    @RunWith(Theories.class)
+    public static class ForDefaultNumberOfInts {
+        static int iterations;
+
+        @Theory
+        public void shouldHold(@ForAll int i) {
+            ++iterations;
+        }
+    }
+
+    @Test
+    public void shouldFeedDefaultNumberOfRandomDoublesToAMarkedDoubleParameter() throws Exception {
+        JUnitCore.runClasses(ForDefaultNumberOfDoubles.class);
+
+        assertEquals(ForAll.class.getMethod("sampleSize").getDefaultValue(), ForDefaultNumberOfDoubles.iterations);
+    }
+
+    @RunWith(Theories.class)
+    public static class ForDefaultNumberOfDoubles {
+        static int iterations;
+
+        @Theory
+        public void shouldHold(@ForAll double d) {
+            ++iterations;
+        }
+    }
+
+    @Test
+    public void shouldFeedDefaultNumberOfRandomStringsToAMarkedStringParameter() throws Exception {
+        JUnitCore.runClasses(ForDefaultNumberOfStrings.class);
+
+        assertEquals(ForAll.class.getMethod("sampleSize").getDefaultValue(), ForDefaultNumberOfStrings.iterations);
+    }
+
+    @RunWith(Theories.class)
+    public static class ForDefaultNumberOfStrings {
+        static int iterations;
+
+        @Theory
+        public void shouldHold(@ForAll String s) {
+            ++iterations;
+        }
+    }
+
+    @Test
+    public void shouldAllowDifferentNumberOfRandomValuesOnAMarkedParameter() {
+        JUnitCore.runClasses(ForDefaultNumberOfStrings.class);
+
+        assertEquals(200, ForDefaultNumberOfStrings.iterations);
+    }
+
+    @RunWith(Theories.class)
+    public static class ForSpecifiedNumberOfStrings {
+        static int iterations;
+
+        @Theory
+        public void shouldHold(@ForAll(sampleSize = 200) String s) {
+            ++iterations;
+        }
+    }
+
+    @Test
+    public void shouldAllowMultipleForAllParmsOnATheoryMethod() {
+        JUnitCore.runClasses(MultipleForAlls.class);
+
+        assertEquals(15, MultipleForAlls.iterations);
+    }
+
+    @RunWith(Theories.class)
+    public static class MultipleForAlls {
+        static int iterations;
+
+        @Theory
+        public void shouldHold(@ForAll(sampleSize = 3) int i, @ForAll(sampleSize = 5) int j) {
+            ++iterations;
+        }
+    }
+
+    @Test
+    public void shouldAllowNonPrimitiveTypesToBeRandomlyGenerated() {
+        JUnitCore.runClasses(NonPrimitiveParameter.class);
+
+        assertEquals(100, RandomDateExtractor.numberOfCalls);
+    }
+
+    @RunWith(Theories.class)
+    public static class NonPrimitiveParameter {
+        @Theory
+        public void shouldHold(@ForAll @ExtractedBy(RandomDateExtractor.class) Date d) {
+            assertNotNull(d);
+        }
+    }
+
+    static class RandomDateExtractor implements RandomValueExtractor {
+        static int numberOfCalls;
+
+        @Override
+        public Object randomValue(SourceOfRandomness random) {
+            ++numberOfCalls;
+            return new Date(random.nextLong());
+        }
+    }
+}