acc: support diffing files in diff.py (#2548)

Using it in #2532

Author: denik

acceptance/bin/diff.py

@@ -30,8 +30,14 @@ def main():
         except re.error as e:
             print(f"Regex error for pattern {r}: {e}", file=sys.stderr)
 
-    files1 = [str(p.relative_to(d1)) for p in d1.rglob("*") if p.is_file()]
-    files2 = [str(p.relative_to(d2)) for p in d2.rglob("*") if p.is_file()]
+    if d1.is_dir() and d2.is_dir():
+        files1 = [str(p.relative_to(d1)) for p in d1.rglob("*") if p.is_file()]
+        files2 = [str(p.relative_to(d2)) for p in d2.rglob("*") if p.is_file()]
+    else:
+        assert d1.is_file(), d1
+        assert d2.is_file(), d2
+        diff_files(patterns, d1, d2)
+        return
 
     set1 = set(files1)
     set2 = set(files2)
@@ -44,13 +50,17 @@ def main():
         elif f not in set1:
             print(f"Only in {d2}: {f}")
         else:
-            a = replaceAll(patterns, p1.read_text()).splitlines(True)
-            b = replaceAll(patterns, p2.read_text()).splitlines(True)
-            if a != b:
-                p1_str = p1.as_posix()
-                p2_str = p2.as_posix()
-                for line in difflib.unified_diff(a, b, p1_str, p2_str, "", "", 2):
-                    print(line, end="")
+            diff_files(patterns, p1, p2)
+
+
+def diff_files(patterns, p1, p2):
+    a = replaceAll(patterns, p1.read_text()).splitlines(True)
+    b = replaceAll(patterns, p2.read_text()).splitlines(True)
+    if a != b:
+        p1_str = p1.as_posix()
+        p2_str = p2.as_posix()
+        for line in difflib.unified_diff(a, b, p1_str, p2_str, "", "", 2):
+            print(line, end="")
 
 
 if __name__ == "__main__":

acceptance/selftest/diff/output.txt

@@ -24,3 +24,14 @@ Only in ../out_dir_b: only_in_b
 +    "id": "[UUID]",
      "userName": "[USERNAME]"
  }
+
+>>> diff.py out_dir_a/output.txt out_dir_b/output.txt
+--- out_dir_a/output.txt
++++ out_dir_b/output.txt
+@@ -1,5 +1,5 @@
+ Hello!
+ {
+-    "id": "[USERID]",
++    "id": "[UUID]",
+     "userName": "[USERNAME]"
+ }

acceptance/selftest/diff/script

@@ -12,11 +12,14 @@ printf "\n\nFooter" >> out_dir_a/output.txt
 printf '{\n    "id": "7d639bad-ac6d-4e6f-abd7-9522a86b0239",\n    "userName": "[USERNAME]"\n}\n\nFooter' >> out_dir_b/output.txt
 
 # Unlike regular diff, diff.py will apply replacements first before doing the comparison
-errcode trace diff.py out_dir_a out_dir_b
+trace diff.py out_dir_a out_dir_b
 
 # Test that it works from non-root directory:
 cd out_dir_a
-errcode trace diff.py . ../out_dir_b
+trace diff.py . ../out_dir_b
 cd ..
 
+# Test diffing files:
+trace diff.py out_dir_a/output.txt out_dir_b/output.txt
+
 rm out_dir_a/only_in_a out_dir_b/only_in_b