Added test cases for #104.

Signed-off-by: Justin Lau <justin@tclau.com>

test/compress/issue-143.js

@@ -0,0 +1,48 @@
+/**
+ * There was an incorrect sort behaviour documented in issue #143:
+ * (x = f(…)) <= x → x >= (x = f(…))
+ *
+ * For example, let the equation be:
+ * (a = parseInt('100')) <= a
+ *
+ * If a was an integer and has the value of 99,
+ * (a = parseInt('100')) <= a → 100 <= 100 → true
+ *
+ * When transformed incorrectly:
+ * a >= (a = parseInt('100')) → 99 >= 100 → false
+ */
+
+tranformation_sort_order_equal: {
+    options = {
+        comparisons: true,
+    };
+
+    input: { (a = parseInt('100')) == a }
+    expect: { (a = parseInt('100')) == a }
+}
+
+tranformation_sort_order_unequal: {
+    options = {
+        comparisons: true,
+    };
+
+    input: { (a = parseInt('100')) != a }
+    expect: { (a = parseInt('100')) != a }
+}
+
+tranformation_sort_order_lesser_or_equal: {
+    options = {
+        comparisons: true,
+    };
+
+    input: { (a = parseInt('100')) <= a }
+    expect: { (a = parseInt('100')) <= a }
+}
+tranformation_sort_order_greater_or_equal: {
+    options = {
+        comparisons: true,
+    };
+
+    input: { (a = parseInt('100')) >= a }
+    expect: { (a = parseInt('100')) >= a }
+}