1 files changed, 110 insertions, 0 deletions
diff --git a/testing/diff_test.ts b/testing/diff_test.ts
new file mode 100644
index 000000000..d2259ba35
--- /dev/null
+++ b/testing/diff_test.ts
@@ -0,0 +1,110 @@
+import diff from "./diff.ts";
+import { test, assertEqual } from "./mod.ts";
+
+test({
+  name: "empty",
+  fn() {
+    assertEqual(diff([], []), []);
+  }
+});
+
+test({
+  name: '"a" vs "b"',
+  fn() {
+    assertEqual(diff(["a"], ["b"]), [
+      { type: "removed", value: "a" },
+      { type: "added", value: "b" }
+    ]);
+  }
+});
+
+test({
+  name: '"a" vs "a"',
+  fn() {
+    assertEqual(diff(["a"], ["a"]), [{ type: "common", value: "a" }]);
+  }
+});
+
+test({
+  name: '"a" vs ""',
+  fn() {
+    assertEqual(diff(["a"], []), [{ type: "removed", value: "a" }]);
+  }
+});
+
+test({
+  name: '"" vs "a"',
+  fn() {
+    assertEqual(diff([], ["a"]), [{ type: "added", value: "a" }]);
+  }
+});
+
+test({
+  name: '"a" vs "a, b"',
+  fn() {
+    assertEqual(diff(["a"], ["a", "b"]), [
+      { type: "common", value: "a" },
+      { type: "added", value: "b" }
+    ]);
+  }
+});
+
+test({
+  name: '"strength" vs "string"',
+  fn() {
+    assertEqual(diff(Array.from("strength"), Array.from("string")), [
+      { type: "common", value: "s" },
+      { type: "common", value: "t" },
+      { type: "common", value: "r" },
+      { type: "removed", value: "e" },
+      { type: "added", value: "i" },
+      { type: "common", value: "n" },
+      { type: "common", value: "g" },
+      { type: "removed", value: "t" },
+      { type: "removed", value: "h" }
+    ]);
+  }
+});
+
+test({
+  name: '"strength" vs ""',
+  fn() {
+    assertEqual(diff(Array.from("strength"), Array.from("")), [
+      { type: "removed", value: "s" },
+      { type: "removed", value: "t" },
+      { type: "removed", value: "r" },
+      { type: "removed", value: "e" },
+      { type: "removed", value: "n" },
+      { type: "removed", value: "g" },
+      { type: "removed", value: "t" },
+      { type: "removed", value: "h" }
+    ]);
+  }
+});
+
+test({
+  name: '"" vs "strength"',
+  fn() {
+    assertEqual(diff(Array.from(""), Array.from("strength")), [
+      { type: "added", value: "s" },
+      { type: "added", value: "t" },
+      { type: "added", value: "r" },
+      { type: "added", value: "e" },
+      { type: "added", value: "n" },
+      { type: "added", value: "g" },
+      { type: "added", value: "t" },
+      { type: "added", value: "h" }
+    ]);
+  }
+});
+
+test({
+  name: '"abc", "c" vs "abc", "bcd", "c"',
+  fn() {
+    assertEqual(diff(["abc", "c"], ["abc", "bcd", "c"]), [
+      { type: "common", value: "abc" },
+      { type: "added", value: "bcd" },
+      { type: "common", value: "c" }
+    ]);
+  }
+});