diff --git a/testdata/cpp-tests-override/fmt_help.golden.stdout b/testdata/cpp-tests-override/fmt_help.golden.stdout
new file mode 100644
index 0000000..e270d6b
--- /dev/null
+++ b/testdata/cpp-tests-override/fmt_help.golden.stdout
@@ -0,0 +1,35 @@
+Jsonnet reformatter v0.17.0
+
+jsonnetfmt {<option>} { <filename> }
+
+Available options:
+  -h / --help                This message
+  -e / --exec                Treat filename as code
+  -o / --output-file <file>  Write to the output file rather than stdout
+  -c / --create-output-dirs  Automatically creates all parent directories for
+                             files
+  -i / --in-place            Update the Jsonnet file(s) in place
+  --test                     Exit with failure if reformatting changed the
+                             file(s)
+  -n / --indent <n>          Number of spaces to indent by
+                             (default 2, 0 means no change)
+  --max-blank-lines <n>      Max vertical spacing (default 2, 0 means no change)
+  --string-style <d|s|l>     Enforce double, single (default) quotes or 'leave'
+  --comment-style <h|s|l>    # (h), // (s) (default), or 'leave'; never changes
+                             she-bang
+  --[no-]pretty-field-names  Use syntax sugar for fields and indexing
+                             (on by default)
+  --[no-]pad-arrays          [ 1, 2, 3 ] instead of [1, 2, 3]
+  --[no-]pad-objects         { x: 1, y: 2 } instead of {x: 1, y: 2}
+                             (on by default)
+  --[no-]sort-imports        Sorting of imports (on by default)
+  --[no-]use-implicit-plus   Remove plus signs where they are not required
+                             (on by default)
+  --version                  Print version
+
+In all cases:
+  <filename> can be - (stdin)
+  Multichar options are expanded e.g. -abc becomes -a -b -c.
+  The -- option suppresses option processing for subsequent arguments.
+  Note that since filenames and jsonnet programs can begin with -, it is
+  advised to use -- if the argument is unknown, e.g. jsonnetfmt -- "$FILENAME".
diff --git a/testdata/cpp-tests-override/fmt_no_args.golden.stderr b/testdata/cpp-tests-override/fmt_no_args.golden.stderr
new file mode 100644
index 0000000..cd473c8
--- /dev/null
+++ b/testdata/cpp-tests-override/fmt_no_args.golden.stderr
@@ -0,0 +1,37 @@
+ERROR: must give filename
+
+Jsonnet reformatter v0.17.0
+
+jsonnetfmt {<option>} { <filename> }
+
+Available options:
+  -h / --help                This message
+  -e / --exec                Treat filename as code
+  -o / --output-file <file>  Write to the output file rather than stdout
+  -c / --create-output-dirs  Automatically creates all parent directories for
+                             files
+  -i / --in-place            Update the Jsonnet file(s) in place
+  --test                     Exit with failure if reformatting changed the
+                             file(s)
+  -n / --indent <n>          Number of spaces to indent by
+                             (default 2, 0 means no change)
+  --max-blank-lines <n>      Max vertical spacing (default 2, 0 means no change)
+  --string-style <d|s|l>     Enforce double, single (default) quotes or 'leave'
+  --comment-style <h|s|l>    # (h), // (s) (default), or 'leave'; never changes
+                             she-bang
+  --[no-]pretty-field-names  Use syntax sugar for fields and indexing
+                             (on by default)
+  --[no-]pad-arrays          [ 1, 2, 3 ] instead of [1, 2, 3]
+  --[no-]pad-objects         { x: 1, y: 2 } instead of {x: 1, y: 2}
+                             (on by default)
+  --[no-]sort-imports        Sorting of imports (on by default)
+  --[no-]use-implicit-plus   Remove plus signs where they are not required
+                             (on by default)
+  --version                  Print version
+
+In all cases:
+  <filename> can be - (stdin)
+  Multichar options are expanded e.g. -abc becomes -a -b -c.
+  The -- option suppresses option processing for subsequent arguments.
+  Note that since filenames and jsonnet programs can begin with -, it is
+  advised to use -- if the argument is unknown, e.g. jsonnetfmt -- "$FILENAME".