feat(cmd): add gofmt-style -l and -d modes to gasm fmt

2026-09-14 18:47:08 +02:00
parent 95f1d6f083
commit 50db6615b2
3 changed files with 258 additions and 1 deletions
@@ -0,0 +1,94 @@
+// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
+// SPDX-License-Identifier: BSD-3-Clause
+
+package main
+
+import (
+	"slices"
+	"strings"
+	"testing"
+)
+
+func lines(ss ...string) []string { return ss }
+
+func TestUnifiedDiffIdentical(t *testing.T) {
+	if got := unifiedDiff("f", lines("a", "b"), lines("a", "b")); got != "" {
+		t.Errorf("identical inputs produced %q, want empty", got)
+	}
+}
+
+func TestUnifiedDiffSingleChange(t *testing.T) {
+	a := lines("1", "2", "3", "4", "5", "6", "7", "8")
+	b := lines("1", "2", "3!", "4", "5", "6", "7", "8")
+	want := "--- f\n+++ f\n" +
+		"@@ -1,6 +1,6 @@\n" +
+		" 1\n 2\n-3\n+3!\n 4\n 5\n 6\n"
+	if got := unifiedDiff("f", a, b); got != want {
+		t.Errorf("diff = %q, want %q", got, want)
+	}
+}
+
+func TestUnifiedDiffInsertAtStart(t *testing.T) {
+	got := unifiedDiff("f", lines("x"), lines("new", "x"))
+	// The single existing line is shown as trailing context, so the hunk
+	// covers it.
+	want := "--- f\n+++ f\n@@ -1,1 +1,2 @@\n+new\n x\n"
+	if got != want {
+		t.Errorf("diff = %q, want %q", got, want)
+	}
+}
+
+func TestUnifiedDiffDeleteAtEnd(t *testing.T) {
+	got := unifiedDiff("f", lines("x", "y"), lines("x"))
+	want := "--- f\n+++ f\n@@ -1,2 +1,1 @@\n x\n-y\n"
+	if got != want {
+		t.Errorf("diff = %q, want %q", got, want)
+	}
+}
+
+func TestUnifiedDiffTwoHunks(t *testing.T) {
+	var a, b []string
+	for i := 1; i <= 20; i++ {
+		a = append(a, itoa(i))
+		b = append(b, itoa(i))
+	}
+	b[1] = "2!"
+	b[17] = "18!"
+	got := unifiedDiff("f", a, b)
+	if !strings.Contains(got, "@@ -1,5 +1,5 @@\n 1\n-2\n+2!\n 3\n 4\n 5\n") {
+		t.Errorf("first hunk wrong:\n%s", got)
+	}
+	if !strings.Contains(got, "@@ -15,6 +15,6 @@\n 15\n 16\n 17\n-18\n+18!\n 19\n 20\n") {
+		t.Errorf("second hunk wrong:\n%s", got)
+	}
+}
+
+// TestUnifiedDiffAdjacentHunks merges changes separated by exactly twice the
+// context into one hunk.
+func TestUnifiedDiffAdjacentHunks(t *testing.T) {
+	a := lines("1", "2", "3", "4", "5", "6", "7", "8")
+	b := slices.Clone(a)
+	b[0] = "1!"
+	b[7] = "8!"
+	got := unifiedDiff("f", a, b)
+	want := "--- f\n+++ f\n" +
+		"@@ -1,8 +1,8 @@\n" +
+		"-1\n+1!\n 2\n 3\n 4\n 5\n 6\n 7\n-8\n+8!\n"
+	if got != want {
+		t.Errorf("diff = %q, want %q", got, want)
+	}
+}
+
+func itoa(n int) string {
+	if n == 0 {
+		return "0"
+	}
+	var buf [4]byte
+	i := len(buf)
+	for n > 0 {
+		i--
+		buf[i] = byte('0' + n%10)
+		n /= 10
+	}
+	return string(buf[i:])
+}