img: add _JfifMarkers.sof

Steve Canny · Steve Canny · commit e080a7d97a4d · 2014-02-27T12:08:35.000-08:00
diff --git a/docx/image/jpeg.py b/docx/image/jpeg.py
@@ -100,7 +100,10 @@ def sof(self):
         """
         First start of frame (SOFn) marker in this sequence.
         """
-        raise NotImplementedError
+        for m in self._markers:
+            if m.marker_code in JPEG_MARKER_CODE.SOF_MARKER_CODES:
+                return m
+        raise KeyError('no start of frame (SOFn) marker in image')
 
 
 class _MarkerParser(object):
diff --git a/tests/image/test_jpeg.py b/tests/image/test_jpeg.py
@@ -97,6 +97,16 @@ def it_raises_if_it_cant_find_the_APP0_marker(self, no_app0_fixture):
         with pytest.raises(KeyError):
             jfif_markers.app0
 
+    def it_can_find_the_SOF_marker(self, sof_fixture):
+        jfif_markers, sof_ = sof_fixture
+        sof = jfif_markers.sof
+        assert sof is sof_
+
+    def it_raises_if_it_cant_find_the_SOF_marker(self, no_sof_fixture):
+        jfif_markers = no_sof_fixture
+        with pytest.raises(KeyError):
+            jfif_markers.sof
+
     # fixtures -------------------------------------------------------
 
     @pytest.fixture
@@ -149,12 +159,23 @@ def no_app0_fixture(self, soi_, eoi_):
         markers = (soi_, eoi_)
         return _JfifMarkers(markers)
 
+    @pytest.fixture
+    def no_sof_fixture(self, soi_, eoi_):
+        markers = (soi_, eoi_)
+        return _JfifMarkers(markers)
+
     @pytest.fixture
     def sof_(self, request):
         return instance_mock(
             request, _SofMarker, marker_code=JPEG_MARKER_CODE.SOF0
         )
 
+    @pytest.fixture
+    def sof_fixture(self, soi_, sof_, eoi_):
+        markers = (soi_, sof_, eoi_)
+        jfif_markers = _JfifMarkers(markers)
+        return jfif_markers, sof_
+
     @pytest.fixture
     def soi_(self, request):
         return instance_mock(
