Use do_run_from_file() for test_funcptr_namecollide

tests/core/test_funcptr_namecollide.in

@@ -0,0 +1,27 @@
+
+      #include <stdio.h>
+
+      void do_call(void (*puts)(const char *), const char *str);
+
+      void do_print(const char *str) {
+        if (!str) do_call(NULL, "delusion");
+        if ((int)str == -1) do_print(str+10);
+        puts("====");
+        puts(str);
+        puts("====");
+      }
+
+      void do_call(void (*puts)(const char *), const char *str) {
+        if (!str) do_print("confusion");
+        if ((int)str == -1) do_call(NULL, str-10);
+        (*puts)(str);
+      }
+
+      int main(int argc, char **argv)
+      {
+        for (int i = 0; i < argc; i++) {
+          do_call(i != 10 ? do_print : NULL, i != 15 ? "waka waka" : NULL);
+        }
+        return 0;
+      }
+    

tests/core/test_funcptr_namecollide.out

@@ -0,0 +1 @@
+waka

tests/test_core.py

@@ -1538,34 +1538,10 @@ class T(RunnerCore): # Short name, to make it more fun to use manually on the co
     self.do_run_from_file(src, output)
 
   def test_funcptr_namecollide(self):
-    src = r'''
-      #include <stdio.h>
+    test_path = path_from_root('tests', 'core', 'test_funcptr_namecollide')
+    src, output = (test_path + s for s in ('.in', '.out'))
 
-      void do_call(void (*puts)(const char *), const char *str);
-
-      void do_print(const char *str) {
-        if (!str) do_call(NULL, "delusion");
-        if ((int)str == -1) do_print(str+10);
-        puts("====");
-        puts(str);
-        puts("====");
-      }
-
-      void do_call(void (*puts)(const char *), const char *str) {
-        if (!str) do_print("confusion");
-        if ((int)str == -1) do_call(NULL, str-10);
-        (*puts)(str);
-      }
-
-      int main(int argc, char **argv)
-      {
-        for (int i = 0; i < argc; i++) {
-          do_call(i != 10 ? do_print : NULL, i != 15 ? "waka waka" : NULL);
-        }
-        return 0;
-      }
-    '''
-    self.do_run(src, 'waka', force_c=True)
+    self.do_run_from_file(src, output, force_c=True)
 
   def test_emptyclass(self):
       if self.emcc_args is None: return self.skip('requires emcc')