Generalise short-arrow test to other sigils.

This fails to reproduce the short BIGARROW issue
which Spencer Bliven reported in #1329, but does
identify a similar corner case with short OCTO
sigils in linear diagrams.

Tests/test_GenomeDiagram.py

@@ -466,50 +466,95 @@ def test_arrow_heads(self):
         self.assertEqual(len(self.gdd.tracks), 4)
         self.finish("GD_sigil_arrows")
 
-    def test_small_arrow_heads(self):
-        """Feature arrow sigil heads within bounding box."""
+    def short_sigils(self, glyph):
+        """Draw sigils on top of grey box backgrounds."""
+        # The blue boxes are only relevant for the BIGARROW
         # Add a track of features, bigger height to emphasise any sigil errors
         self.gdt_features = self.gdd.new_track(1, greytrack=True, height=3)
         # We'll just use one feature set for these features,
         self.gds_features = self.gdt_features.new_set()
-        # Green arrows just have small heads (meaning if there is a mitre
-        # it will escape the bounding box).  Red arrows are small triangles.
+        # For the ARROW and BIGARROW sigils:
+        # - Green arrows just have small heads (meaning if there is a mitre
+        #   it will escape the bounding box).
+        # - Red arrows should be small triangles (so short no shaft shown)
+
+        # Forward strand:
+        feature = SeqFeature(FeatureLocation(15, 30), strand=-1)
+        self.gds_features.add_feature(feature, color="blue")
         feature = SeqFeature(FeatureLocation(15, 30), strand=+1)
         self.gds_features.add_feature(feature, color="grey")
-        self.gds_features.add_feature(feature, name="Forward", sigil="ARROW",
+        self.gds_features.add_feature(feature, name="Forward", sigil=glyph,
                                       arrowhead_length=0.05)
+
+        feature = SeqFeature(FeatureLocation(55, 60), strand=-1)
+        self.gds_features.add_feature(feature, color="blue")
         feature = SeqFeature(FeatureLocation(55, 60), strand=+1)
         self.gds_features.add_feature(feature, color="grey")
-        self.gds_features.add_feature(feature, name="Forward", sigil="ARROW",
+        self.gds_features.add_feature(feature, name="Forward", sigil=glyph,
                                       arrowhead_length=1000, color="red")
+
+        feature = SeqFeature(FeatureLocation(75, 125), strand=-1)
+        self.gds_features.add_feature(feature, color="blue")
         feature = SeqFeature(FeatureLocation(75, 125), strand=+1)
         self.gds_features.add_feature(feature, color="grey")
-        self.gds_features.add_feature(feature, name="Forward", sigil="ARROW",
+        self.gds_features.add_feature(feature, name="Forward", sigil=glyph,
                                       arrowhead_length=0.05)
+
+        # Strandless:
         feature = SeqFeature(FeatureLocation(140, 155), strand=None)
         self.gds_features.add_feature(feature, color="grey")
-        self.gds_features.add_feature(feature, name="Strandless", sigil="ARROW",
+        self.gds_features.add_feature(feature, name="Strandless", sigil=glyph,
                                       arrowhead_length=0.05)
+
         feature = SeqFeature(FeatureLocation(180, 185), strand=None)
         self.gds_features.add_feature(feature, color="grey")
-        self.gds_features.add_feature(feature, name="Strandless", sigil="ARROW",
+        self.gds_features.add_feature(feature, name="Strandless", sigil=glyph,
                                       arrowhead_length=1000, color="red")
+
         feature = SeqFeature(FeatureLocation(200, 250), strand=None)
         self.gds_features.add_feature(feature, color="grey")
-        self.gds_features.add_feature(feature, name="Strandless", sigil="ARROW",
+        self.gds_features.add_feature(feature, name="Strandless", sigil=glyph,
                                       arrowhead_length=0.05)
+
+        # Reverse strand:
+        feature = SeqFeature(FeatureLocation(265, 280), strand=+1)
+        self.gds_features.add_feature(feature, color="blue")
         feature = SeqFeature(FeatureLocation(265, 280), strand=-1)
-        self.gds_features.add_feature(feature, name="Reverse", sigil="ARROW",
+        self.gds_features.add_feature(feature, color="grey")
+        self.gds_features.add_feature(feature, name="Reverse", sigil=glyph,
                                       arrowhead_length=0.05)
+
+        feature = SeqFeature(FeatureLocation(305, 310), strand=+1)
+        self.gds_features.add_feature(feature, color="blue")
         feature = SeqFeature(FeatureLocation(305, 310), strand=-1)
         self.gds_features.add_feature(feature, color="grey")
-        self.gds_features.add_feature(feature, name="Reverse", sigil="ARROW",
+        self.gds_features.add_feature(feature, name="Reverse", sigil=glyph,
                                       arrowhead_length=1000, color="red")
+
+        feature = SeqFeature(FeatureLocation(325, 375), strand=+1)
+        self.gds_features.add_feature(feature, color="blue")
         feature = SeqFeature(FeatureLocation(325, 375), strand=-1)
         self.gds_features.add_feature(feature, color="grey")
-        self.gds_features.add_feature(feature, name="Reverse", sigil="ARROW",
+        self.gds_features.add_feature(feature, name="Reverse", sigil=glyph,
                                       arrowhead_length=0.05)
-        self.finish("GD_sigil_arrows_small")
+
+        self.finish("GD_sigil_short_%s" % glyph)
+
+    def test_short_arrow(self):
+        """Feature arrow sigil heads within bounding box."""
+        self.short_sigils("ARROW")
+
+    def test_short_bigarrow(self):
+        """Feature big-arrow sigil heads within bounding box."""
+        self.short_sigils("BIGARROW")
+
+    def test_short_jaggy(self):
+        """Feature arrow sigil heads within bounding box."""
+        self.short_sigils("JAGGY")
+
+    def test_short_octo(self):
+        """Feature big-arrow sigil heads within bounding box."""
+        self.short_sigils("OCTO")
 
     def long_sigils(self, glyph):
         """Check feature sigils within bounding box."""