test: fix tests for check that compares declarations and file extensi…

…on (#568)

### Summary of Changes

For the test files that compare the declarations in a module with the
file extension:
* Fix file extension
* Fix expected message

tests/resources/validation/other/modules/declarations in stub files/main.sdsstub

@@ -5,29 +5,29 @@ pipeline »myPipeline« {}
 // $TEST$ error "A stub file must not declare pipelines or segments."
 segment »mySegment«() {}
 
-// $TEST$ no error "A pipeline file must only declare pipelines and segments."
+// $TEST$ no error "A stub file must not declare pipelines or segments."
 annotation »MyAnnotation«
-// $TEST$ no error "A pipeline file must only declare pipelines and segments."
+// $TEST$ no error "A stub file must not declare pipelines or segments."
 class »MyClass« {
 
-    // $TEST$ no error "A pipeline file must only declare pipelines and segments."
+    // $TEST$ no error "A stub file must not declare pipelines or segments."
     attr »a«: Int
 
-    // $TEST$ no error "A pipeline file must only declare pipelines and segments."
+    // $TEST$ no error "A stub file must not declare pipelines or segments."
     class »MyNestedClass«
 
-    // $TEST$ no error "A pipeline file must only declare pipelines and segments."
+    // $TEST$ no error "A stub file must not declare pipelines or segments."
     enum »MyEnum«
 
-    // $TEST$ no error "A pipeline file must only declare pipelines and segments."
+    // $TEST$ no error "A stub file must not declare pipelines or segments."
     fun »myFunction«()
 }
-// $TEST$ no error "A pipeline file must only declare pipelines and segments."
+// $TEST$ no error "A stub file must not declare pipelines or segments."
 enum »MyEnum« {
-    // $TEST$ no error "A pipeline file must only declare pipelines and segments."
+    // $TEST$ no error "A stub file must not declare pipelines or segments."
     »MyEnumInstance«
 }
-// $TEST$ no error "A pipeline file must only declare pipelines and segments."
+// $TEST$ no error "A stub file must not declare pipelines or segments."
 fun »myFunction«()
-// $TEST$ no error "A pipeline file must only declare pipelines and segments."
+// $TEST$ no error "A stub file must not declare pipelines or segments."
 schema »MySchema« {}

tests/resources/validation/other/modules/declarations in test files/everything is allowed (no stub errors).sdstest

@@ -0,0 +1,33 @@
+package tests.validation.other.modules.declarationsInTestFiles
+
+// $TEST$ no error "A stub file must not declare pipelines or segments."
+pipeline »myPipeline« {}
+// $TEST$ no error "A stub file must not declare pipelines or segments."
+segment »mySegment«() {}
+
+// $TEST$ no error "A stub file must not declare pipelines or segments."
+annotation »MyAnnotation«
+// $TEST$ no error "A stub file must not declare pipelines or segments."
+class »MyClass« {
+
+    // $TEST$ no error "A stub file must not declare pipelines or segments."
+    attr »a«: Int
+
+    // $TEST$ no error "A stub file must not declare pipelines or segments."
+    class »MyNestedClass«
+
+    // $TEST$ no error "A stub file must not declare pipelines or segments."
+    enum »MyEnum«
+
+    // $TEST$ no error "A stub file must not declare pipelines or segments."
+    fun »myFunction«()
+}
+// $TEST$ no error "A stub file must not declare pipelines or segments."
+enum »MyEnum« {
+    // $TEST$ no error "A stub file must not declare pipelines or segments."
+    »MyEnumInstance«
+}
+// $TEST$ no error "A stub file must not declare pipelines or segments."
+fun »myFunction«()
+// $TEST$ no error "A stub file must not declare pipelines or segments."
+schema »MySchema« {}