Add union assignment tests to analyzer

analyzer/assignment_test.go

@@ -249,6 +249,40 @@ BlueJay.[land] = { }
 `)
 }
 
+func TestAssignmentUnion (test *testing.T) {
+testString (test,
+`
+U: (| Int F64)
+[main] = {
+	x:F64 = 7.7
+	y:U = x
+}
+`)
+}
+
+func TestAssignmentUnionToUnion (test *testing.T) {
+testString (test,
+`
+U: (| Int F64)
+[main] = {
+	x:U y:U
+	x = y
+}
+`)
+}
+
+func TestAssignmentUnionErrNotListed (test *testing.T) {
+testStringErr (test,
+"I64 is not included within union (| Int F64)", 5, 8,
+`
+U: (| Int F64)
+[main] = {
+	x:I64 = 7
+	y:U = x
+}
+`)
+}
+
 func TestAssignmentErrByteSliceString (test *testing.T) {
 testStringErr (test,
 "expected *:Byte", 4, 13,