distance 0 selection

Summary:
This diff adds special handling for the case where a symbol passed to `hh --find-my-tests` is inside a file that contains test classes. In this case, we immediately select it (with distance 0).

Technical details:
Given that `hh --find-my-tests` is just doing a BFS traversal of the call graph at the moment, one may expect that we would handle this case (i.e, distance 0) uniformly with how we already select test files during the traversal. However, there's a bit of a difference in terms of when we find out which file a symbol lives in for the roots vs. the symbols we find on the way. Because of that, the logic for distance 0 is implemented as a special case.

Reviewed By: mheiber

Differential Revision: D83848013

fbshipit-source-id: 241ca89160d2ace03710b6442c455f41106954a0

Author: frank-emrich

hphp/hack/src/server/serverFindMyTests.ml

@@ -232,6 +232,22 @@ let get_references
   in
   List.fold_result search_results ~init:([], []) ~f:resolve_found_position
 
+let is_root_symbol_in_test_file ctx = function
+  | Method { class_name; method_name = _ } ->
+    (match Naming_provider.get_class_path ctx (Utils.add_ns class_name) with
+    | None ->
+      failwith
+        (Printf.sprintf
+           "Could not resolve class %s, even though it was given as part of a root"
+           class_name)
+    | Some relative_path ->
+      let nast = Ast_provider.get_ast ~full:true ctx relative_path in
+      let path = Relative_path.suffix relative_path in
+      if is_test_file ctx path nast then
+        Some path
+      else
+        None)
+
 let search
     ~(ctx : Provider_context.t)
     ~(genv : ServerEnv.genv)
@@ -245,10 +261,12 @@ let search
 
   List.iter roots ~f:(fun root_symbol ->
       let full_name = full_name_of_symbol_def root_symbol in
-      match Hash_set.strict_add seen_symbols full_name with
-      | Result.Ok () ->
-        Queue.enqueue queue { distance = 0; symbol_def = root_symbol }
-      | _ -> ());
+      let seen = Result.is_error (Hash_set.strict_add seen_symbols full_name) in
+      match is_root_symbol_in_test_file ctx root_symbol with
+      | Some test_file -> ignore (Hashtbl.add test_files ~key:test_file ~data:0)
+      | None ->
+        if not seen then
+          Queue.enqueue queue { distance = 0; symbol_def = root_symbol });
 
   let rec bfs () =
     match Queue.dequeue queue with

hphp/hack/test/integration/test_find_my_tests.py

@@ -35,6 +35,7 @@ def check_has_tests_with_distances(
 
         (output, err, retcode) = self.test_driver.run_check(
             options=[
+                "--autostart-server=false",
                 "--json",
                 "--find-my-tests-max-distance",
                 str(max_distance),
@@ -119,6 +120,17 @@ def test_overrides(self) -> None:
             ],
         )
 
+    def test_distance_zero(self) -> None:
+        """Tests that if we ask about a test file itself, it is returned with distance 0
+
+        Uses files from the a/ subdirectory (all of which have prefix A_)
+        """
+
+        self.check_has_tests_with_distances(
+            symbols=["A_SubTest::target"],
+            expected_test_files=[("A_SubTest.php", 0)],
+        )
+
     def test_indirection(self) -> None:
         """Tests that if we set --find-my-tests-max-distance > 1, we get tests that don't call the symbol directly