Fix vectorized contour plot bugs and add tests (#1545)

Author: bdlucas1

mathics/eval/drawing/plot3d_vectorized.py

@@ -225,7 +225,7 @@ def eval_ContourPlot(
     # convert fs of the form a==b to a-b, inplicit contour level 0
     plot_options.functions = list(plot_options.functions)  # so we can modify it
     for i, f in enumerate(plot_options.functions):
-        if f.head == SymbolEqual:
+        if hasattr(f, "head") and f.head == SymbolEqual:
             f = Expression(SymbolSubtract, *f.elements[0:2])
             plot_options.functions[i] = f
             contour_levels = [0]
@@ -264,7 +264,7 @@ def emit(graphics, i, xyzs, quads):
         for level in levels:
             # find contours and add lines
             with Timer("contours"):
-                zgrid = zs.reshape((nx, ny))  # find_contours needs it as an array
+                zgrid = zs.reshape((nx, ny)).T  # find_contours needs it as an array
                 contours = skimage.measure.find_contours(zgrid, level)
 
             # add lines

test/builtin/drawing/test_plot_detail.py

@@ -129,11 +129,6 @@
 print(f"ref_dir {ref_dir}")
 
 
-doc_tests_fn = pathlib.Path(__file__).resolve().parent / "doc_tests.yaml"
-with open(doc_tests_fn) as r:
-    doc_tests = yaml.safe_load(r)
-
-
 def one_test(name, str_expr, vec, opt, act_dir="/tmp"):
     # update name and set use_vectorized_plot depending on
     # whether vectorized test
@@ -190,6 +185,30 @@ def one_test(name, str_expr, vec, opt, act_dir="/tmp"):
         plot.use_vectorized_plot = False
 
 
+def yaml_tests(fn, act_dir, vec):
+    """run a set of tests from yaml file fn"""
+
+    # read the yaml file
+    fn = pathlib.Path(__file__).resolve().parent / fn
+    with open(fn) as r:
+        tests = yaml.safe_load(r)
+
+    # switch to appropriate mode
+    plot.use_vectorized_plot = vec
+
+    for name, info in tests.items():
+        skip = info.get("skip", False)
+        if isinstance(skip, str):
+            skip = {
+                "pyodide": pyodide,  # skip if on pyodide
+                "skimage": not skimage,  # skip if no skimage
+            }[skip]
+        if not skip:
+            one_test(name, info["expr"], vec, ..., act_dir)
+        else:
+            print(f"skipping {name}")
+
+
 def test_all(act_dir="/tmp", opt=None):
     # run twice, once without and once with options
     for use_opt in [False, True]:
@@ -211,17 +230,8 @@ def test_all(act_dir="/tmp", opt=None):
     # the tests above seem so far to be ok on pyodide, but generally they are
     # simpler than these doc_tests
     if not pyodide:
-        for name, info in doc_tests.items():
-            skip = info.get("skip", False)
-            if isinstance(skip, str):
-                skip = {
-                    "pyodide": pyodide,  # skip if on pyodide
-                    "skimage": not skimage,  # skip if no skimage
-                }[skip]
-            if not skip:
-                one_test(name, info["expr"], False, ..., act_dir)
-            else:
-                print(f"skipping {name}")
+        yaml_tests("doc_tests.yaml", act_dir, vec=False)
+        yaml_tests("vec_tests.yaml", act_dir, vec=True)
 
 
 # reference files can be generated by pointing saved actual