Move non-Windows shell stub tests behind //go:build !windows constraint

internal/shell/detect_other_test.go

@@ -0,0 +1,21 @@
+//go:build !windows
+
+package shell
+
+import "testing"
+
+func TestParentShellProcess_NonWindows(t *testing.T) {
+	// On non-Windows, parentShellProcess is a no-op stub that returns "".
+	got := parentShellProcess()
+	if got != "" {
+		t.Fatalf("parentShellProcess() = %q, want empty string on non-Windows", got)
+	}
+}
+
+func TestPreferredPowerShell_NonWindows(t *testing.T) {
+	// On non-Windows, preferredPowerShell returns "powershell".
+	got := preferredPowerShell()
+	if got != "powershell" {
+		t.Fatalf("preferredPowerShell() = %q, want powershell on non-Windows", got)
+	}
+}

internal/shell/detect_test.go

@@ -231,18 +231,3 @@ func TestDetectShellVersion_Branches(t *testing.T) {
 	}
 }
 
-func TestParentShellProcess_NonWindows(t *testing.T) {
-	// On non-Windows, parentShellProcess is a no-op stub that returns "".
-	got := parentShellProcess()
-	if got != "" {
-		t.Fatalf("parentShellProcess() = %q, want empty string on non-Windows", got)
-	}
-}
-
-func TestPreferredPowerShell_NonWindows(t *testing.T) {
-	// On non-Windows, preferredPowerShell returns "powershell".
-	got := preferredPowerShell()
-	if got != "powershell" {
-		t.Fatalf("preferredPowerShell() = %q, want powershell on non-Windows", got)
-	}
-}