test: Lock .yml extension support for spec loading and content-type

Author: thced

src/test/java/com/retailsvc/http/internal/ClasspathResourceHandlerTest.java

@@ -37,6 +37,12 @@ void infersApplicationYamlForYamlExtension() {
         .isEqualTo("application/yaml");
   }
 
+  @Test
+  void infersApplicationYamlForYmlExtension() {
+    assertThat(new ClasspathResourceHandler("/openapi.yml").contentType())
+        .isEqualTo("application/yaml");
+  }
+
   @Test
   void infersTextPlainForTxtExtension() {
     assertThat(new ClasspathResourceHandler("/sample.txt").contentType())

src/test/java/com/retailsvc/http/spec/SpecFromPathTest.java

@@ -31,6 +31,16 @@ void loadsYamlSpecViaSnakeYaml() throws Exception {
     assertThat(spec.operations()).isNotEmpty();
   }
 
+  @Test
+  void loadsYmlSpecViaSnakeYaml() throws Exception {
+    Path resource = Path.of(getClass().getResource("/openapi.yml").toURI());
+
+    Spec spec = Spec.fromPath(resource);
+
+    assertThat(spec.openapi()).startsWith("3.1");
+    assertThat(spec.operations()).isNotEmpty();
+  }
+
   @Test
   void rejectsUnknownExtension(@TempDir Path tmp) throws Exception {
     Path unknown = tmp.resolve("spec.txt");