Add MVP of JUnit adapter (#13)

* Create adapter for JUnit
* Add support for Predicate in Junit adapter

jazon-core/build.gradle

@@ -12,5 +12,4 @@ dependencies {
     annotationProcessor 'org.projectlombok:lombok:1.18.6'
 
     testCompile group: 'org.spockframework', name: 'spock-core', version: '1.2-groovy-2.4'
-    testCompile group: 'junit', name: 'junit', version: '4.12'
 }

jazon-core/src/main/java/com/zendesk/jazon/expectation/DefaultExpectationFactory.java

@@ -7,6 +7,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.function.Predicate;
 
 import static com.zendesk.jazon.expectation.ExpectationFactory.*;
 
@@ -28,6 +29,8 @@ public JsonExpectation expectation(Object object) {
             return expectedUnorderedArray((Set<Object>) object, this);
         } else if (object == null) {
             return new NullExpectation();
+        } else if (object instanceof Predicate) {
+            return new PredicateExpectation((Predicate<Object>) object);
         }
         throw new IllegalArgumentException();
     }

jazon-junit/build.gradle

@@ -0,0 +1,12 @@
+ext {
+    name = 'Jazon JUnit Adapter'
+    description = 'A library for test assertions on JSON payloads - for JUnit framework.'
+}
+
+apply from: '../gradle/publishing.gradle'
+
+dependencies {
+    compile project(':jazon-core')
+    testCompile group: 'junit', name: 'junit', version: '4.12'
+    testCompile group: 'com.google.guava', name: 'guava', version: '27.1-jre'
+}

jazon-junit/src/main/java/com/zendesk/jazon/junit/JazonJunitAdapter.java

@@ -0,0 +1,33 @@
+package com.zendesk.jazon.junit;
+
+import com.zendesk.jazon.MatchResult;
+import com.zendesk.jazon.MatcherFactory;
+import com.zendesk.jazon.actual.GsonActualFactory;
+
+import static com.zendesk.jazon.util.Preconditions.checkNotNull;
+
+public class JazonJunitAdapter {
+    private static final GsonActualFactory GSON_ACTUAL_FACTORY = new GsonActualFactory();
+    private static final MatcherFactory matcherFactory = new MatcherFactory();
+    private final String actualJson;
+
+    public JazonJunitAdapter(String actualJson) {
+        this.actualJson = checkNotNull(actualJson);
+    }
+
+    public static JazonJunitAdapter assertThat(String actualJson) {
+        return new JazonJunitAdapter(actualJson);
+    }
+
+    public void matches(Object expected) {
+        MatchResult matchResult = matcherFactory.matcher()
+                .expected(expected)
+                .actual(GSON_ACTUAL_FACTORY.actual(actualJson))
+                .match();
+        if (matchResult.ok()) {
+            return;
+        }
+        String mismatchMessageTemplate = "\n-----------------------------------\nJSON MISMATCH:\n%s\n-----------------------------------\n";
+        throw new AssertionError(String.format(mismatchMessageTemplate, matchResult.message()));
+    }
+}

jazon-junit/src/test/java/com/zendesk/jazon/junit/ExampleTest.java

@@ -0,0 +1,76 @@
+package com.zendesk.jazon.junit;
+
+import com.google.common.collect.ImmutableMap;
+import org.junit.Test;
+
+import java.util.List;
+import java.util.Map;
+import java.util.function.Predicate;
+
+import static com.zendesk.jazon.junit.JazonJunitAdapter.assertThat;
+import static java.util.Arrays.asList;
+
+
+public class ExampleTest {
+
+    @Test(expected = AssertionError.class)
+    public void simpleTest() {
+        // given
+        String actualJson = "{\"value\": 123}";
+        Map<String, Object> expectedJsonAsMap = ImmutableMap.<String, Object>builder()
+                .put("value", 50)
+                .build();
+
+        // then
+        assertThat(actualJson).matches(expectedJsonAsMap);
+    }
+
+    @Test(expected = AssertionError.class)
+    public void testWithNestedArray() {
+        // given
+        String actualJson = "{" +
+                "\"value\": 50," +
+                "\"tags\": [\"blue\", \"black\", \"red\"]" +
+                "}";
+
+        // then
+        assertThat(actualJson).matches(
+                deal(50, asList("blue", "pink", "red"))
+        );
+    }
+
+    @Test(expected = AssertionError.class)
+    public void testWithRootArray() {
+        // given
+        String actualJson = "[\"blue\", \"black\", \"red\"]";
+
+        // then
+        assertThat(actualJson).matches(asList("blue", "pink", "red"));
+    }
+
+    @Test
+    public void testRegex() {
+        // given
+        String actualJson = "[\"blue\", \"black\", \"red\"]";
+
+        // then
+        assertThat(actualJson).matches(
+                asList(
+                        regex("bl.*"),
+                        regex("bl.*"),
+                        regex("r.*")
+                )
+        );
+    }
+
+    private Predicate<String> regex(String reg) {
+        return s -> s.matches(reg);
+    }
+
+    private static Map<String, Object> deal(int value, List<String> tags) {
+        return ImmutableMap.<String, Object>builder()
+                .put("value", value)
+                .put("tags", tags)
+                .build();
+    }
+}

settings.gradle

@@ -1,4 +1,5 @@
 rootProject.name = 'jazon'
 include 'jazon-core'
 include 'jazon-spock'
+include 'jazon-junit'