ci: Implement the SDK spec as a steps file

Author: khvn26

.github/workflows/sdk-spec.yml

@@ -11,6 +11,7 @@ permissions:
 jobs:
   sdk-spec:
     # Keep the ref in `uses:` and `spec-ref` in sync.
-    uses: Flagsmith/sdk-spec/.github/workflows/run-spec.yml@v0.1.1
+    uses: Flagsmith/sdk-spec/.github/workflows/run-spec.yml@feat/v0.2.0
     with:
-      spec-ref: v0.1.1
+      spec-ref: feat/v0.2.0
+      language: java

sdk-spec/Dockerfile

@@ -0,0 +1,24 @@
+# Runs this SDK, built from source, under the Flagsmith SDK behavioural spec.
+# docker build -f sdk-spec/Dockerfile --build-context harness=<sdk-spec>/harness/java .
+FROM docker.io/library/maven:3.9-eclipse-temurin-11 AS build
+
+WORKDIR /sdk
+COPY pom.xml lombok.config ./
+COPY src/main ./src/main
+RUN mvn --batch-mode --no-transfer-progress \
+      -Dmaven.test.skip=true -Dcheckstyle.skip=true -Djacoco.skip=true -Dmaven.source.skip=true \
+      package dependency:copy-dependencies -DincludeScope=runtime -DoutputDirectory=target/lib \
+ && cp target/flagsmith-java-client-*.jar target/lib/
+
+COPY --from=harness Harness.java /harness/Harness.java
+COPY sdk-spec/Steps.java ./sdk-spec/Steps.java
+RUN javac -cp "target/lib/*" -d target/classes-spec /harness/Harness.java sdk-spec/Steps.java
+
+FROM docker.io/library/eclipse-temurin:11-jre
+
+WORKDIR /sdk
+COPY --from=build /sdk/target/lib ./lib
+COPY --from=build /sdk/target/classes-spec ./classes
+COPY sdk-spec/Steps.java ./sdk-spec/Steps.java
+
+ENTRYPOINT ["java", "-XX:TieredStopAtLevel=1", "-cp", "classes:lib/*", "Harness", "sdk-spec/Steps.java"]

sdk-spec/Steps.java

@@ -0,0 +1,50 @@
+import com.flagsmith.FlagsmithClient;
+import com.flagsmith.exceptions.FlagsmithClientError;
+import com.flagsmith.models.BaseFlag;
+import com.flagsmith.models.Flags;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * Steps for the Flagsmith SDK behavioural spec: https://github.com/Flagsmith/sdk-spec
+ *
+ * <p>Each method implements the Gherkin step in the comment above it.
+ */
+public class Steps {
+
+  /** A flag in the shape the spec expects. */
+  public static class SpecFlag {
+    public final String feature;
+    public final boolean enabled;
+    public final Object value;
+
+    SpecFlag(BaseFlag flag) {
+      feature = flag.getFeatureName();
+      enabled = flag.getEnabled();
+      value = flag.getValue();
+    }
+  }
+
+  static List<SpecFlag> asSpecFlags(Flags flags) {
+    return flags.getAllFlags().stream().map(SpecFlag::new).collect(Collectors.toList());
+  }
+
+  // Given an SDK client for the environment
+  static FlagsmithClient createClient(String environmentKey, String apiUrl) {
+    return FlagsmithClient.newBuilder().setApiKey(environmentKey).withApiUrl(apiUrl).build();
+  }
+
+  // When the application gets the environment flags
+  static List<SpecFlag> getEnvironmentFlags(FlagsmithClient flagsmith)
+      throws FlagsmithClientError {
+    return asSpecFlags(flagsmith.getEnvironmentFlags());
+  }
+
+  // When the application gets the flags for identity "{identifier}" with traits:
+  static List<SpecFlag> getIdentityFlags(
+      FlagsmithClient flagsmith, String identifier, Map<String, Object> traits)
+      throws FlagsmithClientError {
+    return asSpecFlags(flagsmith.getIdentityFlags(identifier, traits));
+  }
+}