add test to FrameAnalysis

testsuite/MDAnalysisTests/analysis/test_base.py

@@ -48,16 +48,34 @@ def __init__(self, reader, **kwargs):
 
     def _prepare(self):
         self.results.found_frames = []
+        self.results.frame_index = []
+        self.results.global_frame_index = []
+        self.results.n_frames = []
+        self.results.global_n_frames = []
+
+        # self.n_frames is defined elsewhere
+        self.global_n_frames = len(self._trajectory[self._global_slicer])
 
     def _single_frame(self):
+        frame_index = self._frame_index
+        global_frame_index = self._global_frame_index
+
         self.results.found_frames.append(self._ts.frame)
+        self.results.frame_index.append(frame_index)
+        self.results.global_frame_index.append(global_frame_index)
+        self.results.n_frames.append(self.n_frames)
+        self.results.global_n_frames.append(self.global_n_frames)
 
     def _conclude(self):
         self.found_frames = list(self.results.found_frames)
 
     def _get_aggregator(self):
         return base.ResultsGroup(
-            {"found_frames": base.ResultsGroup.ndarray_hstack}
+            {"found_frames": base.ResultsGroup.ndarray_hstack,
+             "frame_index": base.ResultsGroup.ndarray_hstack,
+             "global_frame_index": base.ResultsGroup.ndarray_hstack,
+             "n_frames": base.ResultsGroup.ndarray_hstack,
+             "global_n_frames": base.ResultsGroup.ndarray_hstack}
         )
 
 
@@ -450,12 +468,17 @@ def test_frames_times(client_FrameAnalysis):
         start=1, stop=8, step=2, **client_FrameAnalysis
     )
     frames = np.array([1, 3, 5, 7])
-    assert an.n_frames == len(frames)
+    n_frames = len(frames)
+    frame_indices = np.arange(n_frames)
+
+    assert an.n_frames == n_frames
     assert_equal(an.found_frames, frames)
     assert_equal(an.frames, frames, err_msg=FRAMES_ERR)
     assert_allclose(
         an.times, frames * 100, rtol=0, atol=1.5e-4, err_msg=TIMES_ERR
     )
+    assert_equal(an.results.global_frame_index, frame_indices)
+    assert_equal(an.results.global_n_frames, [n_frames] * n_frames)
 
 
 def test_verbose(u):