Add option to copy commit message body

pkg/integration/tests/commit/copy_message_body_to_clipboard.go

@@ -0,0 +1,39 @@
+package commit
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+// We're emulating the clipboard by writing to a file called clipboard
+
+var CopyMessageBodyToClipboard = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Copy a commit message body to the clipboard",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig: func(config *config.AppConfig) {
+		config.GetUserConfig().OS.CopyToClipboardCmd = "printf '%s' {{text}} > clipboard"
+	},
+
+	SetupRepo: func(shell *Shell) {
+		shell.EmptyCommitWithBody("My Subject", "My awesome commit message body")
+	},
+
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Commits().
+			Focus().
+			Lines(
+				Contains("My Subject").IsSelected(),
+			).
+			Press(keys.Commits.CopyCommitAttributeToClipboard)
+
+		t.ExpectPopup().Menu().
+			Title(Equals("Copy to clipboard")).
+			Select(Contains("Commit message body")).
+			Confirm()
+
+		t.ExpectToast(Equals("Commit message body copied to clipboard"))
+
+		t.FileSystem().FileContent("clipboard", Equals("My awesome commit message body"))
+	},
+})