#patch: add Jackson 3 snapshot testing plugin

Author: Botond Somogyi

README.md

@@ -36,6 +36,11 @@ testImplementation 'io.github.origin-energy:java-snapshot-testing-plugin-jackson
 testImplementation 'com.fasterxml.jackson.core:jackson-core:2.11.3'
 testImplementation 'com.fasterxml.jackson.core:jackson-databind:2.11.3'
 
+// For Jackson 3 use the dedicated plugin and serializer classes instead
+testImplementation 'io.github.origin-energy:java-snapshot-testing-plugin-jackson3:4.+'
+testImplementation 'tools.jackson.core:jackson-core:3.1.0'
+testImplementation 'tools.jackson.core:jackson-databind:3.1.0'
+
 // Optional: If you want Jackson to serialize Java 8 date/time types or Optionals you should also add the following dependencies
 testRuntimeOnly 'com.fasterxml.jackson.datatype:jackson-datatype-jdk8:2.11.3'
 testRuntimeOnly 'com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.11.3'
@@ -51,6 +56,10 @@ serializer=au.com.origin.snapshots.serializers.v1.ToStringSnapshotSerializer
 serializer.base64=au.com.origin.snapshots.serializers.v1.Base64SnapshotSerializer
 serializer.json=au.com.origin.snapshots.jackson.serializers.v1.JacksonSnapshotSerializer
 serializer.orderedJson=au.com.origin.snapshots.jackson.serializers.v1.DeterministicJacksonSnapshotSerializer
+
+# Jackson 3 alternative
+# serializer.json=au.com.origin.snapshots.jackson3.serializers.v1.Jackson3SnapshotSerializer
+# serializer.orderedJson=au.com.origin.snapshots.jackson3.serializers.v1.DeterministicJackson3SnapshotSerializer
 comparator=au.com.origin.snapshots.comparators.v1.PlainTextEqualsComparator
 reporters=au.com.origin.snapshots.reporters.v1.PlainTextSnapshotReporter
 snapshot-dir=__snapshots__
@@ -151,14 +160,18 @@ We currently support:
 Plugins
 
 - [Jackson for JSON serialization](https://search.maven.org/search?q=a:java-snapshot-testing-plugin-jackson)
+- [Jackson 3 for JSON serialization](https://search.maven.org/search?q=a:java-snapshot-testing-plugin-jackson3)
     - You need jackson on your classpath (Gradle example)
       ```groovy
-         // Required java-snapshot-testing peer dependencies
+         // Jackson 2 plugin
+         testImplementation 'io.github.origin-energy:java-snapshot-testing-plugin-jackson:4.+'
          testImplementation 'com.fasterxml.jackson.core:jackson-core:2.11.3'
          testImplementation 'com.fasterxml.jackson.core:jackson-databind:2.11.3'
-         // Optional java-snapshot-testing peer dependencies
-         testRuntimeOnly 'com.fasterxml.jackson.datatype:jackson-datatype-jdk8:2.11.3'
-         testRuntimeOnly 'com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.11.3'
+
+         // Jackson 3 plugin
+         testImplementation 'io.github.origin-energy:java-snapshot-testing-plugin-jackson3:4.+'
+         testImplementation 'tools.jackson.core:jackson-core:3.1.0'
+         testImplementation 'tools.jackson.core:jackson-databind:3.1.0'
       ```
 
 ## How does it work?

build.gradle

@@ -32,34 +32,56 @@ subprojects { subproject ->
         mavenCentral()
     }
 
-    tasks.withType(JavaCompile).configureEach {
-        javaCompiler = javaToolchains.compilerFor {
-            languageVersion = JavaLanguageVersion.of(11)
+    if (subproject.name == 'java-snapshot-testing-plugin-jackson3') {
+        tasks.withType(JavaCompile).configureEach {
+            javaCompiler = javaToolchains.compilerFor {
+                languageVersion = JavaLanguageVersion.of(17)
+            }
         }
-    }
 
-    tasks.withType(Javadoc).configureEach {
-        javadocTool = javaToolchains.javadocToolFor {
-            languageVersion = JavaLanguageVersion.of(11)
+        tasks.withType(Javadoc).configureEach {
+            javadocTool = javaToolchains.javadocToolFor {
+                languageVersion = JavaLanguageVersion.of(17)
+            }
         }
-    }
 
-    tasks.withType(Test).configureEach {
-        javaLauncher = javaToolchains.launcherFor {
-            languageVersion = JavaLanguageVersion.of(11)
+        tasks.withType(Test).configureEach {
+            javaLauncher = javaToolchains.launcherFor {
+                languageVersion = JavaLanguageVersion.of(17)
+            }
+        }
+    } else {
+        tasks.withType(JavaCompile).configureEach {
+            javaCompiler = javaToolchains.compilerFor {
+                languageVersion = JavaLanguageVersion.of(11)
+            }
+        }
+
+        tasks.withType(Javadoc).configureEach {
+            javadocTool = javaToolchains.javadocToolFor {
+                languageVersion = JavaLanguageVersion.of(11)
+            }
+        }
+
+        tasks.withType(Test).configureEach {
+            javaLauncher = javaToolchains.launcherFor {
+                languageVersion = JavaLanguageVersion.of(11)
+            }
         }
-    }
 
-    tasks.withType(GroovyCompile).configureEach {
-        javaLauncher = javaToolchains.launcherFor {
-            languageVersion = JavaLanguageVersion.of(11)
+        tasks.withType(GroovyCompile).configureEach {
+            javaLauncher = javaToolchains.launcherFor {
+                languageVersion = JavaLanguageVersion.of(11)
+            }
         }
     }
 
     shadowJar {
         archiveClassifier = ''
-        relocate 'org.assertj', 'shadow.org.assertj'
-        relocate 'org.opentest4j', 'shadow.org.opentest4j'
+        if (subproject.name != 'java-snapshot-testing-plugin-jackson3') {
+            relocate 'org.assertj', 'shadow.org.assertj'
+            relocate 'org.opentest4j', 'shadow.org.opentest4j'
+        }
         exclude 'module-info.class'
     }
 
@@ -82,4 +104,4 @@ subprojects { subproject ->
             exceptionFormat "full"
         }
     }
-}
+}

java-snapshot-testing-plugin-jackson3/build.gradle

@@ -0,0 +1,54 @@
+import org.gradle.api.tasks.compile.JavaCompile
+import org.gradle.api.tasks.javadoc.Javadoc
+import org.gradle.api.tasks.testing.Test
+
+apply from: "../gradle/publishing.gradle"
+apply from: "../gradle/spotless.gradle"
+apply from: "../gradle/junit5.gradle"
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_17
+    targetCompatibility = JavaVersion.VERSION_17
+}
+
+tasks.withType(JavaCompile).configureEach {
+    javaCompiler = javaToolchains.compilerFor {
+        languageVersion = JavaLanguageVersion.of(17)
+    }
+}
+
+tasks.withType(Javadoc).configureEach {
+    javadocTool = javaToolchains.javadocToolFor {
+        languageVersion = JavaLanguageVersion.of(17)
+    }
+}
+
+tasks.withType(Test).configureEach {
+    javaLauncher = javaToolchains.launcherFor {
+        languageVersion = JavaLanguageVersion.of(17)
+    }
+}
+
+dependencies {
+    compileOnly project(':java-snapshot-testing-core')
+
+    compileOnly 'tools.jackson.core:jackson-core:3.1.0'
+    compileOnly 'tools.jackson.core:jackson-databind:3.1.0'
+
+    testImplementation project(':java-snapshot-testing-core')
+    testImplementation "org.slf4j:slf4j-simple:${project.slf4jVersion}"
+    testImplementation "org.assertj:assertj-core:${project.assertjVersion}"
+
+    testImplementation 'tools.jackson.core:jackson-core:3.1.0'
+    testImplementation 'tools.jackson.core:jackson-databind:3.1.0'
+}
+
+publishing {
+    publications {
+        myPublication(MavenPublication) {
+            artifact shadowJar
+            groupId 'io.github.origin-energy'
+            artifactId 'java-snapshot-testing-plugin-jackson3'
+        }
+    }
+}

java-snapshot-testing-plugin-jackson3/src/main/java/au/com/origin/snapshots/jackson3/serializers/DeterministicCollectionModule.java

@@ -0,0 +1,54 @@
+package au.com.origin.snapshots.jackson3.serializers;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Objects;
+import java.util.stream.Collectors;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import tools.jackson.core.JsonGenerator;
+import tools.jackson.databind.SerializationContext;
+import tools.jackson.databind.ValueSerializer;
+import tools.jackson.databind.module.SimpleModule;
+
+/**
+ * Inspired by:
+ * https://www.stubbornjava.com/posts/creating-a-somewhat-deterministic-jackson-objectmapper
+ */
+public class DeterministicCollectionModule extends SimpleModule {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(DeterministicCollectionModule.class);
+
+  public DeterministicCollectionModule() {
+    addSerializer(Collection.class, new CollectionSerializer());
+  }
+
+  private static class CollectionSerializer extends ValueSerializer<Collection> {
+
+    @Override
+    public void serialize(Collection value, JsonGenerator gen, SerializationContext context) {
+      Object[] sorted = convert(value);
+      context.writeValue(gen, sorted);
+    }
+
+    private Object[] convert(Collection<?> value) {
+      if (value == null || value.isEmpty()) {
+        return Collections.emptyList().toArray();
+      }
+
+      try {
+        return value.stream()
+            .filter(Objects::nonNull)
+            .sorted()
+            .collect(Collectors.toList())
+            .toArray();
+      } catch (ClassCastException ex) {
+        LOGGER.warn(
+            "Unable to sort() collection - this may result in a non deterministic snapshot.\n"
+                + "Consider adding a custom serializer for this type via the Jackson3SnapshotSerializer#configure() method.\n"
+                + ex.getMessage());
+        return value.toArray();
+      }
+    }
+  }
+}

java-snapshot-testing-plugin-jackson3/src/main/java/au/com/origin/snapshots/jackson3/serializers/v1/DeterministicJackson3SnapshotSerializer.java

@@ -0,0 +1,24 @@
+package au.com.origin.snapshots.jackson3.serializers.v1;
+
+import au.com.origin.snapshots.jackson3.serializers.DeterministicCollectionModule;
+import tools.jackson.databind.MapperFeature;
+import tools.jackson.databind.json.JsonMapper;
+
+/**
+ * Attempts to deterministically render a snapshot.
+ *
+ * <p>This can help in situations where collections are rendering in a different order on subsequent
+ * runs.
+ *
+ * <p>Note that collections will be ordered which mar or may not be desirable given your use case.
+ */
+public class DeterministicJackson3SnapshotSerializer extends Jackson3SnapshotSerializer {
+
+  @Override
+  protected JsonMapper.Builder configure(JsonMapper.Builder builder) {
+    return super.configure(builder)
+        .enable(MapperFeature.SORT_PROPERTIES_ALPHABETICALLY)
+        .disable(MapperFeature.SORT_CREATOR_PROPERTIES_FIRST)
+        .addModule(new DeterministicCollectionModule());
+  }
+}

java-snapshot-testing-plugin-jackson3/src/main/java/au/com/origin/snapshots/jackson3/serializers/v1/Jackson3SnapshotSerializer.java

@@ -0,0 +1,72 @@
+package au.com.origin.snapshots.jackson3.serializers.v1;
+
+import au.com.origin.snapshots.Snapshot;
+import au.com.origin.snapshots.SnapshotSerializerContext;
+import au.com.origin.snapshots.exceptions.SnapshotExtensionException;
+import au.com.origin.snapshots.serializers.SerializerType;
+import au.com.origin.snapshots.serializers.SnapshotSerializer;
+import com.fasterxml.jackson.annotation.JsonAutoDetect;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import java.util.Arrays;
+import java.util.List;
+import tools.jackson.core.PrettyPrinter;
+import tools.jackson.databind.MapperFeature;
+import tools.jackson.databind.ObjectMapper;
+import tools.jackson.databind.SerializationFeature;
+import tools.jackson.databind.cfg.DateTimeFeature;
+import tools.jackson.databind.json.JsonMapper;
+
+public class Jackson3SnapshotSerializer implements SnapshotSerializer {
+
+  private final PrettyPrinter pp = new SnapshotPrettyPrinter();
+  private final ObjectMapper objectMapper = buildObjectMapper();
+
+  protected JsonMapper.Builder configure(JsonMapper.Builder builder) {
+    return builder;
+  }
+
+  protected boolean shouldFindAndRegisterModules() {
+    return true;
+  }
+
+  private ObjectMapper buildObjectMapper() {
+    JsonMapper.Builder builder =
+        JsonMapper.builder()
+            .enable(SerializationFeature.ORDER_MAP_ENTRIES_BY_KEYS)
+            .disable(DateTimeFeature.WRITE_DATES_AS_TIMESTAMPS)
+            .enable(DateTimeFeature.WRITE_DATES_WITH_ZONE_ID)
+            .disable(SerializationFeature.FAIL_ON_EMPTY_BEANS)
+            .disable(MapperFeature.SORT_PROPERTIES_ALPHABETICALLY)
+            .changeDefaultPropertyInclusion(
+                inclusion -> inclusion.withValueInclusion(JsonInclude.Include.NON_NULL))
+            .changeDefaultVisibility(
+                visibility ->
+                    visibility
+                        .withFieldVisibility(JsonAutoDetect.Visibility.ANY)
+                        .withGetterVisibility(JsonAutoDetect.Visibility.NONE)
+                        .withIsGetterVisibility(JsonAutoDetect.Visibility.NONE)
+                        .withSetterVisibility(JsonAutoDetect.Visibility.NONE)
+                        .withCreatorVisibility(JsonAutoDetect.Visibility.NONE));
+
+    if (shouldFindAndRegisterModules()) {
+      builder.findAndAddModules();
+    }
+    return configure(builder).build();
+  }
+
+  @Override
+  public Snapshot apply(Object object, SnapshotSerializerContext gen) {
+    try {
+      List<?> objects = Arrays.asList(object);
+      String body = objectMapper.writer().with(pp).writeValueAsString(objects);
+      return gen.toSnapshot(body);
+    } catch (Exception e) {
+      throw new SnapshotExtensionException("Jackson Serialization failed", e);
+    }
+  }
+
+  @Override
+  public String getOutputFormat() {
+    return SerializerType.JSON.name();
+  }
+}

java-snapshot-testing-plugin-jackson3/src/main/java/au/com/origin/snapshots/jackson3/serializers/v1/SnapshotPrettyPrinter.java

@@ -0,0 +1,44 @@
+package au.com.origin.snapshots.jackson3.serializers.v1;
+
+import tools.jackson.core.JsonGenerator;
+import tools.jackson.core.util.DefaultIndenter;
+import tools.jackson.core.util.DefaultPrettyPrinter;
+import tools.jackson.core.util.Separators;
+
+class SnapshotPrettyPrinter extends DefaultPrettyPrinter {
+
+  private static final Separators SNAPSHOT_SEPARATORS =
+      Separators.createDefaultInstance().withObjectNameValueSpacing(Separators.Spacing.AFTER);
+
+  public SnapshotPrettyPrinter() {
+    this(SNAPSHOT_SEPARATORS);
+  }
+
+  private SnapshotPrettyPrinter(Separators separators) {
+    super(separators);
+    Indenter lfOnlyIndenter = new DefaultIndenter("  ", "\n");
+    this.indentArraysWith(lfOnlyIndenter);
+    this.indentObjectsWith(lfOnlyIndenter);
+  }
+
+  private SnapshotPrettyPrinter(SnapshotPrettyPrinter base) {
+    super(base);
+  }
+
+  private SnapshotPrettyPrinter(SnapshotPrettyPrinter base, Separators separators) {
+    super(base, separators);
+  }
+
+  @Override
+  public void writeRootValueSeparator(JsonGenerator gen) {}
+
+  @Override
+  public SnapshotPrettyPrinter withSeparators(Separators separators) {
+    return new SnapshotPrettyPrinter(this, separators);
+  }
+
+  @Override
+  public DefaultPrettyPrinter createInstance() {
+    return new SnapshotPrettyPrinter(this);
+  }
+}