diff --git a/evaluator/predicates_test.go b/evaluator/predicates_test.go
new file mode 100644
index 0000000..7549cb0
--- /dev/null
+++ b/evaluator/predicates_test.go
@@ -0,0 +1,26 @@
+package evaluator
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestIsEmpty(t *testing.T) {
+	require.True(t, IsEmpty(false))
+	require.False(t, IsEmpty(true))
+	require.True(t, IsEmpty([]string{}))
+	require.True(t, IsEmpty(map[string]interface{}{}))
+	require.False(t, IsEmpty([]string{""}))
+	require.False(t, IsEmpty(map[string]interface{}{"k": "v"}))
+}
+
+func TestIsTrue(t *testing.T) {
+	require.False(t, IsTrue(nil))
+	require.False(t, IsTrue(false))
+	require.True(t, IsTrue(true))
+	require.True(t, IsTrue(0))
+	require.True(t, IsTrue(""))
+	require.True(t, IsTrue([]string{}))
+	require.True(t, IsTrue(map[string]interface{}{}))
+}