chore: import upstream snapshot with attribution

internal/progress/mode_test.go

@@ -0,0 +1,44 @@
+package progress
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestEnvDisablesColor(t *testing.T) {
+	t.Setenv("NO_COLOR", "")
+	t.Setenv("TERM", "xterm-256color")
+	if envDisablesColor() {
+		t.Error("plain xterm env must not disable color")
+	}
+	t.Setenv("NO_COLOR", "1")
+	if !envDisablesColor() {
+		t.Error("NO_COLOR must disable color")
+	}
+	t.Setenv("NO_COLOR", "")
+	t.Setenv("TERM", "dumb")
+	if !envDisablesColor() {
+		t.Error("TERM=dumb must disable color")
+	}
+}
+
+func TestAnimationAllowedGates(t *testing.T) {
+	var buf bytes.Buffer
+	t.Setenv("GORTEX_FORCE_ANIMATION", "")
+	if animationAllowed(&buf) {
+		t.Error("a non-TTY writer must not animate")
+	}
+	t.Setenv("GORTEX_FORCE_ANIMATION", "1")
+	if !animationAllowed(&buf) {
+		t.Error("GORTEX_FORCE_ANIMATION must override TTY detection")
+	}
+}
+
+func TestRestoreTerminalIdempotent(t *testing.T) {
+	cursorHiddenOnStderr.Store(true)
+	RestoreTerminal()
+	if cursorHiddenOnStderr.Load() {
+		t.Error("RestoreTerminal must clear the hidden-cursor flag")
+	}
+	RestoreTerminal() // second call is a no-op
+}