Function TestParseDiffText_Rename

internal/diff/parser_test.go:12–46

TestParseDiffText_Rename guards against issue #99: a renamed file must be recognized via the "rename from"/"rename to" extended header lines so that the parser reads content at the NEW path instead of warning about the old path ("cannot read file ... exit status 128").

(t *testing.T)

// the parser reads content at the NEW path instead of warning about the old
// path ("cannot read file ... exit status 128").
func TestParseDiffText_Rename(t *testing.T) {
	diffText := `diff --git a/pkg/old name.go b/pkg/new name.go
similarity index 95%
rename from pkg/old name.go
rename to pkg/new name.go
index 1234567..89abcde 100644
--- a/pkg/old name.go
+++ b/pkg/new name.go
@@ -1,3 +1,3 @@
 line1
-line2
+line2 changed
 line3
`
	diffs, err := ParseDiffText(context.Background(), diffText, t.TempDir(), "", nil)
	if err != nil {
		t.Fatalf("ParseDiffText: %v", err)
	}
	if len(diffs) != 1 {
		t.Fatalf("expected 1 diff, got %d", len(diffs))
	}
	d := diffs[0]
	if !d.IsRenamed {
		t.Errorf("IsRenamed = false, want true")
	}
	if d.OldPath != "pkg/old name.go" {
		t.Errorf("OldPath = %q, want %q", d.OldPath, "pkg/old name.go")
	}
	if d.NewPath != "pkg/new name.go" {
		t.Errorf("NewPath = %q, want %q", d.NewPath, "pkg/new name.go")
	}
	if d.IsNew || d.IsDeleted {
		t.Errorf("IsNew/IsDeleted = %v/%v, want false/false", d.IsNew, d.IsDeleted)
	}
}

// TestParseDiffText_PureRename covers a 100% similarity rename, which carries
// no hunks and no ---/+++ lines at all.