Restore addon fixture files B.pyx and C.pyx

Author: jpfeuffer

tests/test_files/.gitignore

@@ -20,5 +20,4 @@ number_conv.pyx
 inherited.pyx
 itertest.pyx
 int_container_class.pyx
-addons/*.pyx
 numpy_vector/*.pyx

tests/test_files/addons/B.pyx

@@ -0,0 +1,10 @@
+from extra cimport M_PI
+
+
+    def super_get(self, int i):
+        cdef _Holder[int] ih
+        ih.set(i+1)
+        return ih.get()
+
+    def get_pi(self):
+        return M_PI

tests/test_files/addons/C.pyx

@@ -0,0 +1,4 @@
+
+
+cdef class CC:
+    cc = 3