Fixed diagnostics files uri handling, added low-level tests

test/solidlsp/haskell/test_haskell_basic.py

@@ -21,6 +21,7 @@ from solidlsp.ls import SolidLanguageServer
 from solidlsp.ls_config import Language
 from solidlsp.ls_types import SymbolKind
 from test.solidlsp.conftest import format_symbol_for_assert, has_malformed_name, request_all_symbols
+from test.solidlsp.util.diagnostics import assert_file_diagnostics
 
 
 @pytest.mark.haskell
@@ -240,3 +241,12 @@ class TestHaskellLanguageServer:
                 for sym in malformed_symbols
             ]
             pytest.fail(f"Found malformed symbols: {diagnostics}", pytrace=False)
+
+    @pytest.mark.parametrize("language_server", [Language.HASKELL], indirect=True)
+    def test_file_diagnostics(self, language_server: SolidLanguageServer) -> None:
+        assert_file_diagnostics(
+            language_server,
+            "src/DiagnosticsSample.hs",
+            (),
+            min_count=1,
+        )