feat: In-memory provider for e2e testing and minimal usage (#546)

* Adds InMemoryProvider to enable simple testing and basic usage

Signed-off-by: liran2000 <liran2000@gmail.com>
Co-authored-by: Todd Baert <todd.baert@dynatrace.com>

.github/workflows/pullrequest.yml

@@ -8,13 +8,6 @@ permissions:
 jobs:
   build:
     runs-on: ubuntu-latest
-    # TODO: this can be removed with https://github.com/open-feature/java-sdk/issues/523
-    services:
-      flagd:
-        image: ghcr.io/open-feature/flagd-testbed:latest
-        ports:
-          - 8013:8013
-
     steps:
       - name: Check out the code
         uses: actions/checkout@96f53100ba2a5449eb71d2e6604bbcd94b9449b5

CONTRIBUTING.md

@@ -18,14 +18,9 @@ If you're adding tests to cover something in the spec, use the `@Specification`
 
 ## End-to-End Tests
 
-<!-- TODO: this section should be updated with https://github.com/open-feature/java-sdk/issues/523 -->
+The continuous integration runs a set of [gherkin e2e tests](https://github.com/open-feature/test-harness/blob/main/features/evaluation.feature) using `InMemoryProvider`.
 
-The continuous integration runs a set of [gherkin e2e tests](https://github.com/open-feature/test-harness/blob/main/features/evaluation.feature) using [`flagd`](https://github.com/open-feature/flagd). These tests do not run with the default maven profile. If you'd like to run them locally, you can start the flagd testbed with
-
-```
-docker run -p 8013:8013 ghcr.io/open-feature/flagd-testbed:latest
-```
-and then run 
+to run alone:
 ```
 mvn test -P e2e-test
 ```

pom.xml

@@ -11,8 +11,6 @@
     <maven.compiler.source>1.8</maven.compiler.source>
     <maven.compiler.target>${maven.compiler.source}</maven.compiler.target>
     <junit.jupiter.version>5.10.0</junit.jupiter.version>
-    <!-- exclusion expression for e2e tests -->
-    <testExclusions>**/e2e/*.java</testExclusions>
     <module-name>${groupId}.${artifactId}</module-name>
   </properties>
 
@@ -21,10 +19,10 @@
   <url>https://openfeature.dev</url>
   <developers>
     <developer>
-       <id>abrahms</id>
-       <name>Justin Abrahms</name>
-       <organization>eBay</organization>
-       <url>https://justin.abrah.ms/</url>
+      <id>abrahms</id>
+      <name>Justin Abrahms</name>
+      <organization>eBay</organization>
+      <url>https://justin.abrah.ms/</url>
     </developer>
   </developers>
   <licenses>
@@ -120,9 +118,9 @@
     </dependency>
 
     <dependency>
-        <groupId>io.cucumber</groupId>
-        <artifactId>cucumber-junit-platform-engine</artifactId>
-        <scope>test</scope>
+      <groupId>io.cucumber</groupId>
+      <artifactId>cucumber-junit-platform-engine</artifactId>
+      <scope>test</scope>
     </dependency>
 
     <dependency>
@@ -139,39 +137,33 @@
       <scope>test</scope>
     </dependency>
 
-    <dependency>
-      <groupId>dev.openfeature.contrib.providers</groupId>
-      <artifactId>flagd</artifactId>
-      <version>0.5.10</version>
-      <scope>test</scope>
-    </dependency>
-
     <dependency>
       <groupId>org.awaitility</groupId>
       <artifactId>awaitility</artifactId>
       <version>4.2.0</version>
       <scope>test</scope>
     </dependency>
+
   </dependencies>
 
   <dependencyManagement>
     <dependencies>
 
-        <dependency>
-            <groupId>io.cucumber</groupId>
-            <artifactId>cucumber-bom</artifactId>
-            <version>7.13.0</version>
-            <type>pom</type>
-            <scope>import</scope>
-        </dependency>
-
-        <dependency>
-            <groupId>org.junit</groupId>
-            <artifactId>junit-bom</artifactId>
-            <version>5.10.0</version>
-            <type>pom</type>
-            <scope>import</scope>
-        </dependency>
+      <dependency>
+        <groupId>io.cucumber</groupId>
+        <artifactId>cucumber-bom</artifactId>
+        <version>7.13.0</version>
+        <type>pom</type>
+        <scope>import</scope>
+      </dependency>
+
+      <dependency>
+        <groupId>org.junit</groupId>
+        <artifactId>junit-bom</artifactId>
+        <version>5.10.0</version>
+        <type>pom</type>
+        <scope>import</scope>
+      </dependency>
 
     </dependencies>
   </dependencyManagement>
@@ -203,7 +195,7 @@
           </execution>
         </executions>
       </plugin>
-     
+
       <plugin>
         <artifactId>maven-dependency-plugin</artifactId>
         <version>3.6.0</version>
@@ -249,7 +241,7 @@
           <excludes>
             <!-- tests to exclude -->
             <exclude>${testExclusions}</exclude>
-         </excludes>
+          </excludes>
         </configuration>
       </plugin>
 
@@ -271,7 +263,7 @@
 
         <executions>
           <execution>
-      	    <id>prepare-agent</id>
+            <id>prepare-agent</id>
             <goals>
               <goal>prepare-agent</goal>
             </goals>
@@ -319,7 +311,7 @@
                 </rule>
               </rules>
             </configuration>
- 	        </execution>
+          </execution>
 
         </executions>
       </plugin>
@@ -496,14 +488,11 @@
     </profile>
 
     <profile>
-      <!-- this profile handles running the flagd e2e tests -->
-      <!-- TODO: this profile can likely be removed with TODO: this section should be updated with https://github.com/open-feature/java-sdk/issues/523 -->
-      <!-- TODO: we should pull the submodule and run these tests unconditionall once flagd isn't required -->
       <id>e2e-test</id>
       <properties>
         <!-- run the e2e tests by clearing the exclusions -->
         <testExclusions/>
-      </properties>  
+      </properties>
       <build>
         <plugins>
           <!-- pull the gherkin tests as a git submodule  -->

src/main/java/dev/openfeature/sdk/FlagEvaluationDetails.java

@@ -40,6 +40,7 @@ public static <T> FlagEvaluationDetails<T> from(ProviderEvaluation<T> providerEv
                 .value(providerEval.getValue())
                 .variant(providerEval.getVariant())
                 .reason(providerEval.getReason())
+                .errorMessage(providerEval.getErrorMessage())
                 .errorCode(providerEval.getErrorCode())
                 .flagMetadata(providerEval.getFlagMetadata())
                 .build();

src/main/java/dev/openfeature/sdk/Structure.java

@@ -9,6 +9,8 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
+import static dev.openfeature.sdk.Value.objectToValue;
+
 /**
  * {@link Structure} represents a potentially nested object type which is used to represent 
  * structured data.
@@ -123,4 +125,16 @@ default <T extends Structure> Map<String, Value> merge(Function<Map<String, Valu
         }
         return merged;
     }
+
+    /**
+     * Transform an object map to a {@link Structure} type.
+     *
+     * @param map map of objects
+     * @return a Structure object in the SDK format
+     */
+    static Structure mapToStructure(Map<String, Object> map) {
+        return new MutableStructure(map.entrySet().stream()
+            .filter(e -> e.getValue() != null)
+            .collect(Collectors.toMap(Map.Entry::getKey, e -> objectToValue(e.getValue()))));
+    }
 }

src/main/java/dev/openfeature/sdk/Value.java

@@ -5,10 +5,13 @@
 import java.util.Map;
 import java.util.stream.Collectors;
 
+import dev.openfeature.sdk.exceptions.TypeMismatchError;
 import lombok.EqualsAndHashCode;
 import lombok.SneakyThrows;
 import lombok.ToString;
 
+import static dev.openfeature.sdk.Structure.mapToStructure;
+
 /**
  * Values serve as a generic return type for structure data from providers.
  * Providers may deal in JSON, protobuf, XML or some other data-interchange format.
@@ -280,4 +283,38 @@ protected Value clone() {
         }
         return new Value(this.asObject());
     }
+
+    /**
+     * Wrap an object into a Value.
+     *
+     * @param object the object to wrap
+     * @return the wrapped object
+     */
+    public static Value objectToValue(Object object) {
+        if (object instanceof Value) {
+            return (Value) object;
+        } else if (object == null) {
+            return null;
+        } else if (object instanceof String) {
+            return new Value((String) object);
+        } else if (object instanceof Boolean) {
+            return new Value((Boolean) object);
+        } else if (object instanceof Integer) {
+            return new Value((Integer) object);
+        } else if (object instanceof Double) {
+            return new Value((Double) object);
+        } else if (object instanceof Structure) {
+            return new Value((Structure) object);
+        } else if (object instanceof List) {
+            return new Value(((List<Object>) object).stream()
+                .map(o -> objectToValue(o))
+                .collect(Collectors.toList()));
+        } else if (object instanceof Instant) {
+            return new Value((Instant) object);
+        } else if (object instanceof Map) {
+            return new Value(mapToStructure((Map<String, Object>) object));
+        } else {
+            throw new TypeMismatchError("Flag value " + object + " had unexpected type " + object.getClass() + ".");
+        }
+    }
 }

src/main/java/dev/openfeature/sdk/providers/memory/ContextEvaluator.java

@@ -0,0 +1,12 @@
+package dev.openfeature.sdk.providers.memory;
+
+import dev.openfeature.sdk.EvaluationContext;
+
+/**
+ * Context evaluator - use for resolving flag according to evaluation context, for handling targeting.
+ * @param <T> expected value type
+ */
+public interface ContextEvaluator<T> {
+
+    T evaluate(Flag flag, EvaluationContext evaluationContext);
+}

src/main/java/dev/openfeature/sdk/providers/memory/Flag.java

@@ -0,0 +1,21 @@
+package dev.openfeature.sdk.providers.memory;
+
+import lombok.Builder;
+import lombok.Getter;
+import lombok.Singular;
+import lombok.ToString;
+
+import java.util.Map;
+
+/**
+ * Flag representation for the in-memory provider.
+ */
+@ToString
+@Builder
+@Getter
+public class Flag<T> {
+    @Singular
+    private Map<String, Object> variants;
+    private String defaultVariant;
+    private ContextEvaluator<T> contextEvaluator;
+}