diff --git a/ui/build/environment_test.go b/ui/build/environment_test.go
index 0294dac..37f500f 100644
--- a/ui/build/environment_test.go
+++ b/ui/build/environment_test.go
@@ -56,6 +56,15 @@
 	}
 }
 
+func TestEnvAllow(t *testing.T) {
+	initial := &Environment{"TEST=1", "TEST2=0", "TEST3=2"}
+	initial.Allow("TEST3", "TEST")
+	got := initial.Environ()
+	if len(got) != 2 || got[0] != "TEST=1" || got[1] != "TEST3=2" {
+		t.Errorf("Expected [TEST=1 TEST3=2], got: %v", got)
+	}
+}
+
 const testKatiEnvFileContents = `#!/bin/sh
 # Generated by kati unknown