test: invalid car content type params

gateway/handler_car_test.go

@@ -110,6 +110,30 @@ func TestCarParams(t *testing.T) {
 			require.Equal(t, test.expectedDuplicates.String(), params.Duplicates.String())
 		}
 	})
+
+	t.Run("buildCarParams from Accept header: order and dups parsing (invalid)", func(t *testing.T) {
+		t.Parallel()
+
+		// below ensure the implicit default (DFS and no duplicates) is correctly inferred
+		// from the value read from Accept header
+		tests := []string{
+			"application/vnd.ipld.car; dups=invalid",
+			"application/vnd.ipld.car; order=invalid",
+			"application/vnd.ipld.car; order=dfs; dups=invalid",
+			"application/vnd.ipld.car; order=invalid; dups=y",
+		}
+		for _, test := range tests {
+			r := mustNewRequest(t, http.MethodGet, "http://example.com/", nil)
+			r.Header.Set("Accept", test)
+
+			mediaType, formatParams, err := customResponseFormat(r)
+			assert.NoError(t, err)
+			assert.Equal(t, carResponseFormat, mediaType)
+
+			_, err = buildCarParams(r, formatParams)
+			assert.ErrorContains(t, err, "unsupported application/vnd.ipld.car content type")
+		}
+	})
 }
 
 func TestContentTypeFromCarParams(t *testing.T) {