test(version): add unit tests for version behavior

internal/version/version_test.go

@@ -0,0 +1,84 @@
+package version
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestVersionFunctions(t *testing.T) {
+	origVersion := Version
+	origBuildDate := BuildDate
+	origCommit := Commit
+	defer func() {
+		Version = origVersion
+		BuildDate = origBuildDate
+		Commit = origCommit
+	}()
+
+	tests := []struct {
+		name      string
+		version   string
+		buildDate string
+		commit    string
+		wantFull  string
+		wantShort string
+	}{
+		{
+			name:      "Default dev version",
+			version:   "dev",
+			buildDate: "unknown",
+			commit:    "unknown",
+			wantFull:  "tunnel_pls dev (commit: unknown, built: unknown)",
+			wantShort: "dev",
+		},
+		{
+			name:      "Release version",
+			version:   "v1.0.0",
+			buildDate: "2026-01-23",
+			commit:    "abcdef123",
+			wantFull:  "tunnel_pls v1.0.0 (commit: abcdef123, built: 2026-01-23)",
+			wantShort: "v1.0.0",
+		},
+		{
+			name:      "Empty values",
+			version:   "",
+			buildDate: "",
+			commit:    "",
+			wantFull:  "tunnel_pls  (commit: , built: )",
+			wantShort: "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			Version = tt.version
+			BuildDate = tt.buildDate
+			Commit = tt.commit
+
+			gotFull := GetVersion()
+			if gotFull != tt.wantFull {
+				t.Errorf("GetVersion() = %q, want %q", gotFull, tt.wantFull)
+			}
+
+			gotShort := GetShortVersion()
+			if gotShort != tt.wantShort {
+				t.Errorf("GetShortVersion() = %q, want %q", gotShort, tt.wantShort)
+			}
+		})
+	}
+}
+
+func TestGetVersion_Format(t *testing.T) {
+	v := "1.2.3"
+	c := "brainrot"
+	d := "now"
+
+	Version = v
+	Commit = c
+	BuildDate = d
+
+	expected := fmt.Sprintf("tunnel_pls %s (commit: %s, built: %s)", v, c, d)
+	if GetVersion() != expected {
+		t.Errorf("GetVersion() formatting mismatch")
+	}
+}