TRX-1066: fix(core): exclude accept.notAllowed violations on 204 responses (#414)

Author: pboos

openapi-validation-api/src/main/java/com/getyourguide/openapi/validation/api/Rules.java

@@ -5,6 +5,7 @@ public static class Request {
         public static final String PATH_MISSING = "validation.request.path.missing";
         public static final String OPERATION_NOT_ALLOWED = "validation.request.operation.notAllowed";
         public static final String BODY_SCHEMA_ONE_OF = "validation.request.body.schema.oneOf";
+        public static final String ACCEPT_NOT_ALLOWED = "validation.request.accept.notAllowed";
     }
 
     public static class Response {

openapi-validation-core/src/main/java/com/getyourguide/openapi/validation/core/exclusions/InternalViolationExclusions.java

@@ -12,7 +12,8 @@ public class InternalViolationExclusions {
     private final ViolationExclusions customViolationExclusions;
 
     public boolean isExcluded(OpenApiViolation violation) {
-        return falsePositive404(violation)
+        return falsePositive204(violation)
+            || falsePositive404(violation)
             || falsePositive405(violation)
             || falsePositive406(violation)
             || falsePositiveRequestWith4xxResponse(violation)
@@ -31,6 +32,11 @@ private static boolean oneOfMatchesMoreThanOneSchema(OpenApiViolation violation)
             .matches(".*Instance failed to match exactly one schema \\(matched [1-9][0-9]* out of \\d+\\).*");
     }
 
+    private boolean falsePositive204(OpenApiViolation violation) {
+        return violation.getResponseStatus().orElse(0) == 204
+            && Rules.Request.ACCEPT_NOT_ALLOWED.equals(violation.getRule());
+    }
+
     private boolean falsePositive404(OpenApiViolation violation) {
         return
             (

openapi-validation-core/src/test/java/com/getyourguide/openapi/validation/core/exclusions/InternalViolationExclusionsTest.java

@@ -29,6 +29,7 @@ public void whenViolationThenViolationNotExcluded() {
         checkViolationNotExcluded(buildSimpleViolation(Direction.RESPONSE, 404));
         checkViolationNotExcluded(buildSimpleViolation(Direction.RESPONSE, 400));
         checkViolationNotExcluded(buildSimpleViolation(Direction.REQUEST, 200));
+        checkViolationNotExcluded(buildSimpleViolation(Direction.REQUEST, 204));
         checkViolationNotExcluded(buildSimpleViolation(Direction.REQUEST, null));
         checkViolationNotExcluded(buildSimpleViolation(Direction.RESPONSE, 200));
     }
@@ -159,6 +160,30 @@ public void when406ResponseCodeWithStatusUnknownViolationThenViolationExcluded()
             .build());
     }
 
+    @Test
+    public void when204ResponseCodeWithAcceptNotAllowedViolationThenViolationExcluded() {
+        when(customViolationExclusions.isExcluded(any())).thenReturn(false);
+
+        checkViolationExcluded(buildAcceptNotAllowedViolation(204));
+    }
+
+    @Test
+    public void whenNon204ResponseCodeWithAcceptNotAllowedViolationThenViolationNotExcluded() {
+        when(customViolationExclusions.isExcluded(any())).thenReturn(false);
+
+        checkViolationNotExcluded(buildAcceptNotAllowedViolation(200));
+    }
+
+    private static OpenApiViolation buildAcceptNotAllowedViolation(int responseStatus) {
+        return OpenApiViolation.builder()
+            .direction(Direction.REQUEST)
+            .rule("validation.request.accept.notAllowed")
+            .responseStatus(responseStatus)
+            .message("Request Accept header '[application/json]' does not match any defined response types. "
+                + "Must be one of: [application/problem+json].")
+            .build();
+    }
+
     @Test
     public void whenUnknownErrorWithConcurrentModificationExceptionThenViolationExcluded() {
         when(customViolationExclusions.isExcluded(any())).thenReturn(false);