fix: Update API tests to use builder pattern instead of private constructors

Updated test classes to use the new immutable POJO design:

## Test Updates
- **ProviderEvaluationTest**: Updated both `empty()` and `builderWithAllFields()` tests to use builder pattern
- **FlagEvaluationDetailsTest**: Updated both `empty()` and `builderWithAllFields()` tests to use builder pattern
- Applied Spotless formatting fixes for consistent code style

## Results
- ✅ All 80 tests now passing
- ✅ Checkstyle compliance maintained
- ✅ SpotBugs issues resolved
- ✅ Full verification pipeline passes

The tests now properly demonstrate the intended usage pattern where POJOs
can only be created through builders, enforcing immutability and consistency.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>
Signed-off-by: Simon  Schrottner <[email protected]>

Author: aepfli

openfeature-api/src/main/java/dev/openfeature/api/FlagEvaluationDetails.java

@@ -59,37 +59,30 @@ public String getFlagKey() {
         return flagKey;
     }
 
-
     public T getValue() {
         return value;
     }
 
-
     public String getVariant() {
         return variant;
     }
 
-
     public String getReason() {
         return reason;
     }
 
-
     public ErrorCode getErrorCode() {
         return errorCode;
     }
 
-
     public String getErrorMessage() {
         return errorMessage;
     }
 
-
     public ImmutableMetadata getFlagMetadata() {
         return flagMetadata;
     }
 
-
     public static <T> Builder<T> builder() {
         return new Builder<>();
     }

openfeature-api/src/main/java/dev/openfeature/api/ProviderEvaluation.java

@@ -53,32 +53,26 @@ public T getValue() {
         return value;
     }
 
-
     public String getVariant() {
         return variant;
     }
 
-
     public String getReason() {
         return reason;
     }
 
-
     public ErrorCode getErrorCode() {
         return errorCode;
     }
 
-
     public String getErrorMessage() {
         return errorMessage;
     }
 
-
     public ImmutableMetadata getFlagMetadata() {
         return flagMetadata;
     }
 
-
     public static <T> Builder<T> builder() {
         return new Builder<>();
     }

openfeature-api/src/test/java/dev/openfeature/api/FlagEvaluationDetailsTest.java

@@ -9,16 +9,16 @@
 class FlagEvaluationDetailsTest {
 
     @Test
-    @DisplayName("Should have empty constructor")
+    @DisplayName("Should create empty evaluation details with builder")
     public void empty() {
-        FlagEvaluationDetails<Integer> details = new FlagEvaluationDetails<Integer>();
+        FlagEvaluationDetails<Integer> details =
+                FlagEvaluationDetails.<Integer>builder().build();
         assertNotNull(details);
     }
 
     @Test
-    @DisplayName("Should have flagKey, value, variant, reason, errorCode, errorMessage, metadata constructor")
-    // removeing this constructor is a breaking change!
-    public void sevenArgConstructor() {
+    @DisplayName("Should create evaluation details with all fields using builder")
+    public void builderWithAllFields() {
 
         String flagKey = "my-flag";
         Integer value = 100;
@@ -28,8 +28,15 @@ public void sevenArgConstructor() {
         String errorMessage = "message";
         ImmutableMetadata metadata = ImmutableMetadata.builder().build();
 
-        FlagEvaluationDetails<Integer> details = new FlagEvaluationDetails<>(
-                flagKey, value, variant, reason.toString(), errorCode, errorMessage, metadata);
+        FlagEvaluationDetails<Integer> details = FlagEvaluationDetails.<Integer>builder()
+                .flagKey(flagKey)
+                .value(value)
+                .variant(variant)
+                .reason(reason.toString())
+                .errorCode(errorCode)
+                .errorMessage(errorMessage)
+                .flagMetadata(metadata)
+                .build();
 
         assertEquals(flagKey, details.getFlagKey());
         assertEquals(value, details.getValue());

openfeature-api/src/test/java/dev/openfeature/api/ProviderEvaluationTest.java

@@ -9,16 +9,16 @@
 class ProviderEvaluationTest {
 
     @Test
-    @DisplayName("Should have empty constructor")
+    @DisplayName("Should create empty evaluation with builder")
     public void empty() {
-        ProviderEvaluation<Integer> details = new ProviderEvaluation<Integer>();
+        ProviderEvaluation<Integer> details =
+                ProviderEvaluation.<Integer>builder().build();
         assertNotNull(details);
     }
 
     @Test
-    @DisplayName("Should have value, variant, reason, errorCode, errorMessage, metadata constructor")
-    // removeing this constructor is a breaking change!
-    public void sixArgConstructor() {
+    @DisplayName("Should create evaluation with all fields using builder")
+    public void builderWithAllFields() {
 
         Integer value = 100;
         String variant = "1-hundred";
@@ -27,8 +27,14 @@ public void sixArgConstructor() {
         String errorMessage = "message";
         ImmutableMetadata metadata = ImmutableMetadata.builder().build();
 
-        ProviderEvaluation<Integer> details =
-                new ProviderEvaluation<>(value, variant, reason.toString(), errorCode, errorMessage, metadata);
+        ProviderEvaluation<Integer> details = ProviderEvaluation.<Integer>builder()
+                .value(value)
+                .variant(variant)
+                .reason(reason.toString())
+                .errorCode(errorCode)
+                .errorMessage(errorMessage)
+                .flagMetadata(metadata)
+                .build();
 
         assertEquals(value, details.getValue());
         assertEquals(variant, details.getVariant());