diff --git a/pro/src/conflictLogic.ts b/pro/src/conflictLogic.ts
index dfff399..f9744c2 100644
--- a/pro/src/conflictLogic.ts
+++ b/pro/src/conflictLogic.ts
@@ -38,9 +38,11 @@ export function isMergable(a: Entity, b?: Entity) {
  * @param b
  */
 function mergeDigInModified(a: string, o: string, b: string) {
-  const { conflict, result } = mergeDigIn(a, o, b);
+  const { conflict, result } = mergeDigIn(a, o, b, {
+    stringSeparator: /\n/,
+  });
   for (let index = 0; index < result.length; ++index) {
-    if (["<<<<<<<", "=======", ">>>>>>>"].contains(result[index])) {
+    if (["<<<<<<<", "=======", ">>>>>>>"].includes(result[index])) {
       result[index] = "`" + result[index] + "`";
     }
   }
@@ -72,7 +74,7 @@ function getLCSText(a: string, b: string) {
  * @param b
  * @returns
  */
-function twoWayMerge(a: string, b: string): string {
+export function twoWayMerge(a: string, b: string): string {
   const aa = a.trim();
   const bb = b.trim();
   if (aa === "" && bb === "") {
@@ -88,7 +90,10 @@ function twoWayMerge(a: string, b: string): string {
   // const c = getLCSText(a, b);
   // const patches = makePatches(c, a);
   // const [d] = applyPatches(patches, b);
-  const c = getLCSText(a, b);
+  const c = getLCSText(a, b); //.trim();
+  // console.debug(`(start) LCS Text:`);
+  // console.debug(c);
+  // console.debug(`(end) LCS Text.`);
   const d = mergeDigInModified(a, c, b).result.join("\n");
   return d;
 }
@@ -100,7 +105,7 @@ function twoWayMerge(a: string, b: string): string {
  * @param orig
  * @returns
  */
-function threeWayMerge(a: string, b: string, orig: string) {
+export function threeWayMerge(a: string, b: string, orig: string) {
   return mergeDigInModified(a, orig, b).result.join("\n");
 }
 
diff --git a/pro/tests/conflictLogic.test.ts b/pro/tests/conflictLogic.test.ts
index f9b56e1..162a502 100644
--- a/pro/tests/conflictLogic.test.ts
+++ b/pro/tests/conflictLogic.test.ts
@@ -1,5 +1,9 @@
 import { deepStrictEqual, rejects, throws } from "assert";
-import { getFileRenameForDup } from "../src/conflictLogic";
+import {
+  getFileRenameForDup,
+  threeWayMerge,
+  twoWayMerge,
+} from "../src/conflictLogic";
 
 describe("New name is generated", () => {
   it("should throw for empty file", async () => {
@@ -69,3 +73,224 @@ describe("New name is generated", () => {
     );
   });
 });
+
+describe("Two way merge", () => {
+  it("should correctly merge from zero files", async () => {
+    const a = "aaa";
+    const b = "bbb";
+    const res = twoWayMerge(a, b);
+    const expected = `\`<<<<<<<\`
+aaa
+\`=======\`
+bbb
+\`>>>>>>>\``;
+    deepStrictEqual(expected, res);
+  });
+
+  it("should correctly merge from common lines", async () => {
+    const a = `
+Something is cool. 中文1
+Other thing is cooler. 哈哈！
+`;
+    const b = `
+Anything is cool. 中文2
+Other thing is cooler. 哈哈！
+`;
+    const res = twoWayMerge(a, b);
+    // console.log(res);
+    const expected = `
+\`<<<<<<<\`
+Something is cool. 中文1
+\`=======\`
+Anything is cool. 中文2
+\`>>>>>>>\`
+Other thing is cooler. 哈哈！
+`;
+    deepStrictEqual(expected, res);
+  });
+
+  it("should merge by lines", async () => {
+    const a = `
+Something is cool. 中文1
+`;
+    const b = `
+Something is cooler. 中文2
+`;
+    const res = twoWayMerge(a, b);
+    // console.log(res);
+    const expected = `
+\`<<<<<<<\`
+Something is cool. 中文1
+\`=======\`
+Something is cooler. 中文2
+\`>>>>>>>\`
+`;
+    deepStrictEqual(expected, res);
+  });
+});
+
+describe("Three way merge", () => {
+  it("should correctly merge from zero files", async () => {
+    const orig = "";
+    const a = "aaa";
+    const b = "bbb";
+    const res = threeWayMerge(a, b, orig);
+    const expected = `\`<<<<<<<\`
+aaa
+\`=======\`
+bbb
+\`>>>>>>>\``;
+    deepStrictEqual(expected, res);
+  });
+
+  it("should correctly merge after adding lines on both sides", async () => {
+    const orig = `
+* [ ] A1
+* [ ] A2
+* [ ] A3
+`;
+    const a = `
+* [ ] A1
+* [ ] new line after A1
+* [ ] A2
+* [ ] A3
+`;
+    const b = `
+* [ ] A1
+* [ ] A2
+* [ ] New line after A2
+* [ ] A3
+`;
+    const res = threeWayMerge(a, b, orig);
+    // console.log(res);
+    const expected = `
+* [ ] A1
+* [ ] new line after A1
+* [ ] A2
+* [ ] New line after A2
+* [ ] A3
+`;
+    deepStrictEqual(expected, res);
+  });
+
+  it("should correctly merge after adding lines on both sides (again)", async () => {
+    const orig = `
+* [ ] 中文
+* [ ] にほんご／にっぽんご
+* [ ] A3
+`;
+    const a = `
+* [ ] 中文
+* [ ] new line after 中文
+* [ ] にほんご／にっぽんご
+* [ ] A3
+`;
+    const b = `
+* [ ] 中文
+* [ ] にほんご／にっぽんご
+* [ ] New line after にほんご／にっぽんご
+* [ ] A3
+`;
+    const res = threeWayMerge(a, b, orig);
+    // console.log(res);
+    const expected = `
+* [ ] 中文
+* [ ] new line after 中文
+* [ ] にほんご／にっぽんご
+* [ ] New line after にほんご／にっぽんご
+* [ ] A3
+`;
+    deepStrictEqual(expected, res);
+  });
+
+  it("should correctly merge after deleting lines on both sides", async () => {
+    const orig = `
+* [ ] 中文
+* [ ] にほんご／にっぽんご
+* [ ] A3
+* [ ] A4
+`;
+    const a = `
+* [ ] にほんご／にっぽんご
+* [ ] A3
+* [ ] A4
+`;
+    const b = `
+* [ ] 中文
+* [ ] A3
+* [ ] A4
+`;
+    const res = threeWayMerge(a, b, orig);
+    // console.log(res);
+    const expected = `
+\`<<<<<<<\`
+* [ ] にほんご／にっぽんご
+\`=======\`
+* [ ] 中文
+\`>>>>>>>\`
+* [ ] A3
+* [ ] A4
+`;
+    deepStrictEqual(expected, res);
+  });
+
+  it("should correctly merge after adding on one side and deleting on other side", async () => {
+    const orig = `
+* [ ] 中文
+* [ ] A3
+* [ ] A4
+`;
+    const a = `
+* [ ] 中文
+* [ ] にほんご／にっぽんご
+* [ ] A3
+* [ ] A4
+`;
+    const b = `
+* [ ] A3
+* [ ] A4
+`;
+    const res = threeWayMerge(a, b, orig);
+    // console.log(res);
+    const expected = `
+\`<<<<<<<\`
+* [ ] 中文
+* [ ] にほんご／にっぽんご
+\`=======\`
+\`>>>>>>>\`
+* [ ] A3
+* [ ] A4
+`;
+    deepStrictEqual(expected, res);
+  });
+
+  it("should correctly merge after adding on one side and deleting on other side (again)", async () => {
+    const orig = `
+* [ ] 中文
+* [ ] A3
+* [ ] A4
+`;
+    const a = `
+* [ ] A3
+* [ ] A4
+`;
+    const b = `
+* [ ] 中文
+* [ ] にほんご／にっぽんご
+* [ ] A3
+* [ ] A4
+`;
+    const res = threeWayMerge(a, b, orig);
+    // console.log(res);
+    const expected = `
+\`<<<<<<<\`
+\`=======\`
+* [ ] 中文
+* [ ] にほんご／にっぽんご
+\`>>>>>>>\`
+* [ ] A3
+* [ ] A4
+`;
+    deepStrictEqual(expected, res);
+  });
+});