Move git command to git/gitcmd (#35483)

The name cmd is already used in many places and may cause conflicts, so
I chose `gitcmd` instead to minimize potential naming conflicts.

modules/git/gitcmd/command_test.go

@@ -0,0 +1,77 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package gitcmd
+
+import (
+	"fmt"
+	"os"
+	"testing"
+
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/tempdir"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMain(m *testing.M) {
+	gitHomePath, cleanup, err := tempdir.OsTempDir("gitea-test").MkdirTempRandom("git-home")
+	if err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "unable to create temp dir: %v", err)
+		os.Exit(1)
+	}
+	defer cleanup()
+
+	setting.Git.HomePath = gitHomePath
+}
+
+func TestRunWithContextStd(t *testing.T) {
+	cmd := NewCommand("--version")
+	stdout, stderr, err := cmd.RunStdString(t.Context(), &RunOpts{})
+	assert.NoError(t, err)
+	assert.Empty(t, stderr)
+	assert.Contains(t, stdout, "git version")
+
+	cmd = NewCommand("--no-such-arg")
+	stdout, stderr, err = cmd.RunStdString(t.Context(), &RunOpts{})
+	if assert.Error(t, err) {
+		assert.Equal(t, stderr, err.Stderr())
+		assert.Contains(t, err.Stderr(), "unknown option:")
+		assert.Contains(t, err.Error(), "exit status 129 - unknown option:")
+		assert.Empty(t, stdout)
+	}
+
+	cmd = NewCommand()
+	cmd.AddDynamicArguments("-test")
+	assert.ErrorIs(t, cmd.Run(t.Context(), &RunOpts{}), ErrBrokenCommand)
+
+	cmd = NewCommand()
+	cmd.AddDynamicArguments("--test")
+	assert.ErrorIs(t, cmd.Run(t.Context(), &RunOpts{}), ErrBrokenCommand)
+
+	subCmd := "version"
+	cmd = NewCommand().AddDynamicArguments(subCmd) // for test purpose only, the sub-command should never be dynamic for production
+	stdout, stderr, err = cmd.RunStdString(t.Context(), &RunOpts{})
+	assert.NoError(t, err)
+	assert.Empty(t, stderr)
+	assert.Contains(t, stdout, "git version")
+}
+
+func TestGitArgument(t *testing.T) {
+	assert.True(t, isValidArgumentOption("-x"))
+	assert.True(t, isValidArgumentOption("--xx"))
+	assert.False(t, isValidArgumentOption(""))
+	assert.False(t, isValidArgumentOption("x"))
+
+	assert.True(t, isSafeArgumentValue(""))
+	assert.True(t, isSafeArgumentValue("x"))
+	assert.False(t, isSafeArgumentValue("-x"))
+}
+
+func TestCommandString(t *testing.T) {
+	cmd := NewCommand("a", "-m msg", "it's a test", `say "hello"`)
+	assert.Equal(t, cmd.prog+` a "-m msg" "it's a test" "say \"hello\""`, cmd.LogString())
+
+	cmd = NewCommand("url: https://a:b@c/", "/root/dir-a/dir-b")
+	assert.Equal(t, cmd.prog+` "url: https://sanitized-credential@c/" .../dir-a/dir-b`, cmd.LogString())
+}