Make cygwin gate tests non-vacuous via pure shouldStyle

Bugbot correctly flagged that the cygwin regression tests used
non-terminal writers (temp files, bytes.Buffer), so IsTerminalWriter
returned false before the TERM check was ever reached — they passed
identically with or without the fix.

Split the decision into a pure shouldStyle(noColor, term,
isTerminalWriter) so tests can simulate a terminal writer and actually
reach the NO_COLOR and TERM gates, and drop the vacuous tests in
status_test.go and mdrender_test.go that asserted outcomes already
guaranteed by the writer check.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: alishakawaguchi

cmd/entire/cli/interactive/interactive.go

@@ -97,20 +97,28 @@ func IsTerminalWriter(w io.Writer) bool {
 // legacy consoles that can't handle ANSI escapes are excluded, and otherwise
 // the answer is whether w is a terminal.
 func ShouldStyle(w io.Writer) bool {
-	if os.Getenv("NO_COLOR") != "" {
+	return shouldStyle(os.Getenv("NO_COLOR"), os.Getenv("TERM"), IsTerminalWriter(w))
+}
+
+// shouldStyle is the pure decision behind ShouldStyle, split out so tests can
+// exercise the NO_COLOR/TERM gates with a simulated terminal writer — `go
+// test` never has a real one, so testing through ShouldStyle would
+// short-circuit on the terminal check and never reach the earlier gates.
+func shouldStyle(noColor, term string, isTerminalWriter bool) bool {
+	if noColor != "" {
 		return false
 	}
-	if termLacksANSI() {
+	if termLacksANSI(term) {
 		return false
 	}
-	return IsTerminalWriter(w)
+	return isTerminalWriter
 }
 
-// termLacksANSI reports whether the current TERM identifies a legacy console
-// that does not reliably handle ANSI escape sequences. The canonical case is
+// termLacksANSI reports whether term identifies a legacy console that does
+// not reliably handle ANSI escape sequences. The canonical case is
 // TERM=cygwin: writing the ESC byte (0x1B) ends up rendered as the CP437
 // glyph U+2190 LEFTWARDS ARROW ("←") instead of starting an SGR sequence, so
 // styled output appears as literal text like "←[32m●←[m" (see GH #1267).
-func termLacksANSI() bool {
-	return os.Getenv("TERM") == "cygwin"
+func termLacksANSI(term string) bool {
+	return term == "cygwin"
 }

cmd/entire/cli/interactive/interactive_test.go

@@ -95,45 +95,44 @@ func TestIsTerminalWriter_Pipe(t *testing.T) {
 	}
 }
 
-func TestTermLacksANSI(t *testing.T) {
+// TestShouldStyle_Gates exercises the pure decision with a simulated
+// terminal writer (isTerminalWriter=true) so the NO_COLOR and TERM gates are
+// actually reached — `go test` has no real terminal, so calling ShouldStyle
+// directly would short-circuit on the terminal check and pass vacuously.
+// TERM=cygwin case is the regression test for GH #1267.
+func TestShouldStyle_Gates(t *testing.T) {
+	t.Parallel()
 	cases := []struct {
-		term string
-		want bool
+		name       string
+		noColor    string
+		term       string
+		isTerminal bool
+		want       bool
 	}{
-		{"cygwin", true},
-		{"xterm-256color", false},
-		{"dumb", false},
-		{"", false},
+		{"terminal with ANSI-capable TERM", "", "xterm-256color", true, true},
+		{"TERM=cygwin disables on a terminal", "", "cygwin", true, false},
+		{"NO_COLOR disables on a terminal", "1", "xterm-256color", true, false},
+		{"non-terminal writer disables", "", "xterm-256color", false, false},
+		{"TERM=dumb defers to the terminal check", "", "dumb", true, true},
+		{"empty TERM defers to the terminal check", "", "", true, true},
 	}
 	for _, c := range cases {
-		t.Run(c.term, func(t *testing.T) {
-			t.Setenv("TERM", c.term)
-			if got := termLacksANSI(); got != c.want {
-				t.Errorf("termLacksANSI() with TERM=%q = %v; want %v", c.term, got, c.want)
+		t.Run(c.name, func(t *testing.T) {
+			t.Parallel()
+			if got := shouldStyle(c.noColor, c.term, c.isTerminal); got != c.want {
+				t.Errorf("shouldStyle(%q, %q, %v) = %v; want %v",
+					c.noColor, c.term, c.isTerminal, got, c.want)
 			}
 		})
 	}
 }
 
-// TestShouldStyle exercises the disabling gates; the enabling path needs a
-// real terminal writer, which `go test` doesn't provide.
-func TestShouldStyle(t *testing.T) {
-	t.Run("NO_COLOR disables", func(t *testing.T) {
-		t.Setenv("NO_COLOR", "1")
-		if ShouldStyle(os.Stdout) {
-			t.Error("ShouldStyle(os.Stdout) = true with NO_COLOR set; want false")
-		}
-	})
-	t.Run("TERM=cygwin disables", func(t *testing.T) {
-		t.Setenv("TERM", "cygwin")
-		if ShouldStyle(os.Stdout) {
-			t.Error("ShouldStyle(os.Stdout) = true with TERM=cygwin; want false")
-		}
-	})
-	t.Run("non-terminal writer disables", func(t *testing.T) {
-		t.Setenv("TERM", "xterm-256color")
-		if ShouldStyle(&bytes.Buffer{}) {
-			t.Error("ShouldStyle(*bytes.Buffer) = true; want false")
-		}
-	})
+// TestShouldStyle_ReadsEnv verifies the exported wrapper plumbs the process
+// env into the decision: NO_COLOR is the first gate, so it disables styling
+// regardless of whether stdout is a terminal.
+func TestShouldStyle_ReadsEnv(t *testing.T) {
+	t.Setenv("NO_COLOR", "1")
+	if ShouldStyle(os.Stdout) {
+		t.Error("ShouldStyle(os.Stdout) = true with NO_COLOR set; want false")
+	}
 }

cmd/entire/cli/mdrender/mdrender_test.go

@@ -107,21 +107,6 @@ func TestRenderForWriter_NoColorEnvForcesRaw(t *testing.T) {
 	}
 }
 
-// TERM=cygwin must fall back to raw markdown; see interactive.termLacksANSI.
-// Regression test for GH #1267.
-func TestRenderForWriter_TermCygwinForcesRaw(t *testing.T) {
-	t.Setenv("TERM", "cygwin")
-
-	const md = "# Heading"
-	out, err := mdrender.RenderForWriter(&bytes.Buffer{}, md)
-	if err != nil {
-		t.Fatalf("RenderForWriter: %v", err)
-	}
-	if out != md {
-		t.Errorf("expected raw markdown when TERM=cygwin, got: %q", out)
-	}
-}
-
 // TestRender_EmptyInputDoesNotPanic verifies the renderer handles edge cases
 // (empty string, whitespace-only) without erroring.
 func TestRender_EmptyInputDoesNotPanic(t *testing.T) {

cmd/entire/cli/status_test.go

@@ -961,43 +961,6 @@ func TestShouldUseColor_RegularFile(t *testing.T) {
 	}
 }
 
-// TERM=cygwin must disable color; see interactive.termLacksANSI.
-// Regression test for GH #1267.
-func TestShouldUseColor_TermCygwinDisables(t *testing.T) {
-	t.Setenv("TERM", "cygwin")
-
-	f, err := os.CreateTemp(t.TempDir(), "test")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer f.Close()
-
-	if shouldUseColor(f) {
-		t.Error("shouldUseColor should be false when TERM=cygwin")
-	}
-}
-
-// formatSettingsStatusShort should not emit any ESC (0x1B) bytes when
-// TERM=cygwin. Regression test for GH #1267.
-func TestFormatSettingsStatusShort_TermCygwinNoEscapes(t *testing.T) {
-	t.Setenv("TERM", "cygwin")
-
-	f, err := os.CreateTemp(t.TempDir(), "tty")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer f.Close()
-
-	sty := newStatusStyles(f)
-	out := formatSettingsStatusShort(context.Background(), &EntireSettings{Enabled: true}, sty)
-	if strings.ContainsRune(out, 0x1B) {
-		t.Errorf("output contains ESC (0x1B) under TERM=cygwin: %q", out)
-	}
-	if strings.ContainsRune(out, '←') {
-		t.Errorf("output contains U+2190 LEFTWARDS ARROW under TERM=cygwin: %q", out)
-	}
-}
-
 func TestNewStatusStyles_NonTTY(t *testing.T) {
 	t.Parallel()
 

cmd/entire/cli/uiform/uiform.go

@@ -21,7 +21,7 @@ func IsAccessibleMode() bool {
 
 // Theme returns Entire's standard huh theme.
 //
-//nolint:ireturn // huh.Theme is an interface in v2
+
 func Theme() huh.Theme {
 	return huh.ThemeFunc(huh.ThemeDracula)
 }