Fix non-Windows terminals assumed to always support 256-color

pkg/term/console.go

@@ -4,11 +4,12 @@
 package term
 
 import (
+	"errors"
 	"os"
 )
 
 func enableVirtualTerminalProcessing(f *os.File) error {
-	return nil
+	return errors.New("not implemented")
 }
 
 func openTTY() (*os.File, error) {

pkg/term/env_test.go

@@ -0,0 +1,114 @@
+// Package term provides information about the terminal that the current process is connected to (if any),
+// for example measuring the dimensions of the terminal and inspecting whether it's safe to output color.
+package term
+
+import (
+	"testing"
+)
+
+func TestFromEnv(t *testing.T) {
+	tests := []struct {
+		name          string
+		env           map[string]string
+		wantTerminal  bool
+		wantColor     bool
+		want256Color  bool
+		wantTrueColor bool
+	}{
+		{
+			name: "default",
+			env: map[string]string{
+				"GH_FORCE_TTY":   "",
+				"CLICOLOR":       "",
+				"CLICOLOR_FORCE": "",
+				"NO_COLOR":       "",
+				"TERM":           "",
+				"COLORTERM":      "",
+			},
+			wantTerminal:  false,
+			wantColor:     false,
+			want256Color:  false,
+			wantTrueColor: false,
+		},
+		{
+			name: "force color",
+			env: map[string]string{
+				"GH_FORCE_TTY":   "",
+				"CLICOLOR":       "",
+				"CLICOLOR_FORCE": "1",
+				"NO_COLOR":       "",
+				"TERM":           "",
+				"COLORTERM":      "",
+			},
+			wantTerminal:  false,
+			wantColor:     true,
+			want256Color:  false,
+			wantTrueColor: false,
+		},
+		{
+			name: "force tty",
+			env: map[string]string{
+				"GH_FORCE_TTY":   "true",
+				"CLICOLOR":       "",
+				"CLICOLOR_FORCE": "",
+				"NO_COLOR":       "",
+				"TERM":           "",
+				"COLORTERM":      "",
+			},
+			wantTerminal:  true,
+			wantColor:     true,
+			want256Color:  false,
+			wantTrueColor: false,
+		},
+		{
+			name: "has 256-color support",
+			env: map[string]string{
+				"GH_FORCE_TTY":   "true",
+				"CLICOLOR":       "",
+				"CLICOLOR_FORCE": "",
+				"NO_COLOR":       "",
+				"TERM":           "256-color",
+				"COLORTERM":      "",
+			},
+			wantTerminal:  true,
+			wantColor:     true,
+			want256Color:  true,
+			wantTrueColor: false,
+		},
+		{
+			name: "has truecolor support",
+			env: map[string]string{
+				"GH_FORCE_TTY":   "true",
+				"CLICOLOR":       "",
+				"CLICOLOR_FORCE": "",
+				"NO_COLOR":       "",
+				"TERM":           "truecolor",
+				"COLORTERM":      "",
+			},
+			wantTerminal:  true,
+			wantColor:     true,
+			want256Color:  true,
+			wantTrueColor: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			for key, value := range tt.env {
+				t.Setenv(key, value)
+			}
+			terminal := FromEnv()
+			if got := terminal.IsTerminalOutput(); got != tt.wantTerminal {
+				t.Errorf("expected terminal %v, got %v", tt.wantTerminal, got)
+			}
+			if got := terminal.IsColorEnabled(); got != tt.wantColor {
+				t.Errorf("expected color %v, got %v", tt.wantColor, got)
+			}
+			if got := terminal.Is256ColorSupported(); got != tt.want256Color {
+				t.Errorf("expected 256-color %v, got %v", tt.want256Color, got)
+			}
+			if got := terminal.IsTrueColorSupported(); got != tt.wantTrueColor {
+				t.Errorf("expected truecolor %v, got %v", tt.wantTrueColor, got)
+			}
+		})
+	}
+}