March gen: refactor for easier testing

tools/gen_marching_cubes_conf.py

@@ -171,7 +171,7 @@ def all_transforms():
     return output
 
 
-def do_main(base_cases):
+def gen_index(base_cases):
     transforms = all_transforms()
     index = [None for x in range(256)]
     for case in base_cases:
@@ -197,21 +197,32 @@ def do_main(base_cases):
     if has_unbound:
         raise RuntimeError("Some cases were not generated.")
 
-    print(PREAMBLE)
+    return index
-    print(("static const TriVect edges_of_intersection[256] = {"))
+
+
+def pretty_print(index):
+    output = ""
+    output += PREAMBLE
+    output += "static const TriVect edges_of_intersection[256] = {\n"
 
     for (case_id, case) in enumerate(index):
-        print("\tTriVect({")
+        output += "\tTriVect({\n"
 
         for (tri_id, tri) in enumerate(case.triangles):
-            print('\t\t' + dump_tri(tri),
+            output += '\t\t{}{}'.format(
-                  end=",\n" if tri_id != len(case.triangles) - 1 else '\n')
+                dump_tri(tri),
-        print('\t\t})', end=',\n' if case_id != len(index) - 1 else '\n')
+                ",\n" if tri_id != len(case.triangles) - 1 else '\n')
-    print("};")
+        output += '\t\t})' + (',\n' if case_id != len(index) - 1 else '\n')
+    output += "};\n"
+
+    return output
 
 
-def main():
+def do_main(base_cases):
-    base_cases = [
+    print(pretty_print(gen_index(base_cases)))
+
+
+BASE_CASES = [
     # Source: <https://en.wikipedia.org/wiki/File:MarchingCubes.svg>
     # -- 1 --
     TriangulatedCube(set(), []),
@@ -555,7 +566,10 @@ def main():
             ],
         ]),
 ]
-    do_main(base_cases)
+
+
+def main():
+    do_main(BASE_CASES)
 
 
 if __name__ == "__main__":