diff --git a/src/go/types/api_test.go b/src/go/types/api_test.go
index fe3950a..798c09b 100644
--- a/src/go/types/api_test.go
+++ b/src/go/types/api_test.go
@@ -1232,6 +1232,41 @@
 	}
 }
 
+func TestConvertibleTo(t *testing.T) {
+	for _, test := range []struct {
+		v, t Type
+		want bool
+	}{
+		{Typ[Int], Typ[Int], true},
+		{Typ[Int], Typ[Float32], true},
+		{newDefined(Typ[Int]), Typ[Int], true},
+		{newDefined(new(Struct)), new(Struct), true},
+		{newDefined(Typ[Int]), new(Struct), false},
+		{Typ[UntypedInt], Typ[Int], true},
+	} {
+		if got := ConvertibleTo(test.v, test.t); got != test.want {
+			t.Errorf("ConvertibleTo(%v, %v) = %t, want %t", test.v, test.t, got, test.want)
+		}
+	}
+}
+
+func TestAssignableTo(t *testing.T) {
+	for _, test := range []struct {
+		v, t Type
+		want bool
+	}{
+		{Typ[Int], Typ[Int], true},
+		{Typ[Int], Typ[Float32], false},
+		{newDefined(Typ[Int]), Typ[Int], false},
+		{newDefined(new(Struct)), new(Struct), true},
+		{Typ[UntypedBool], Typ[Bool], true},
+	} {
+		if got := AssignableTo(test.v, test.t); got != test.want {
+			t.Errorf("AssignableTo(%v, %v) = %t, want %t", test.v, test.t, got, test.want)
+		}
+	}
+}
+
 func TestIdentical_issue15173(t *testing.T) {
 	// Identical should allow nil arguments and be symmetric.
 	for _, test := range []struct {