diff --git a/src/core/diff/strategies/__tests__/new-unified.test.ts b/src/core/diff/strategies/__tests__/new-unified.test.ts
new file mode 100644
index 0000000..a7fd279
--- /dev/null
+++ b/src/core/diff/strategies/__tests__/new-unified.test.ts
@@ -0,0 +1,312 @@
+import { NewUnifiedDiffStrategy } from '../new-unified';
+
+describe('main', () => {
+
+  let strategy: NewUnifiedDiffStrategy
+
+  beforeEach(() => {
+      strategy = new NewUnifiedDiffStrategy()
+  })
+
+  describe('getToolDescription', () => {
+      it('should return tool description with correct cwd', () => {
+          const cwd = '/test/path'
+          const description = strategy.getToolDescription(cwd)
+          
+          expect(description).toContain('apply_diff')
+          expect(description).toContain(cwd)
+          expect(description).toContain('Parameters:')
+          expect(description).toContain('Format Requirements:')
+      })
+  })
+
+  it('should apply simple diff correctly', async () => {
+    const original = `line1
+line2
+line3`;
+
+    const diff = `--- a/file.txt
++++ b/file.txt
+@@ ... @@
+ line1
++new line
+ line2
+-line3
++modified line3`;
+
+    const result = await strategy.applyDiff(original, diff);
+    
+    expect(result).toBe(`line1
+new line
+line2
+modified line3`);
+  });
+
+  it('should handle multiple hunks', async () => {
+    const original = `line1
+line2
+line3
+line4
+line5`;
+
+    const diff = `--- a/file.txt
++++ b/file.txt
+@@ ... @@
+ line1
++new line
+ line2
+-line3
++modified line3
+@@ ... @@
+ line4
+-line5
++modified line5
++new line at end`;
+
+    const result = await strategy.applyDiff(original, diff);
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.content).toBe(`line1
+new line
+line2
+modified line3
+line4
+modified line5
+new line at end`);
+    }
+  });
+
+  it('should handle complex large', async () => {
+    const original = `line1
+line2
+line3
+line4
+line5
+line6
+line7
+line8
+line9
+line10`;
+
+    const diff = `--- a/file.txt
++++ b/file.txt
+@@ ... @@
+ line1
++header line
++another header
+ line2
+-line3
+-line4
++modified line3
++modified line4
++extra line
+@@ ... @@
+ line6
++middle section
+ line7
+-line8
++changed line8
++bonus line
+@@ ... @@
+ line9
+-line10
++final line
++very last line`;
+
+    const result = await strategy.applyDiff(original, diff);
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.content).toBe(`line1
+header line
+another header
+line2
+modified line3
+modified line4
+extra line
+line5
+line6
+middle section
+line7
+changed line8
+bonus line
+line9
+final line
+very last line`);
+    }
+  });
+
+  it('should handle indentation changes', async () => {
+    const original = `first line
+  indented line
+    double indented line
+  back to single indent
+no indent
+  indented again
+    double indent again
+      triple indent
+  back to single
+last line`;
+
+    const diff = `--- original
++++ modified
+@@ ... @@
+ first line
+   indented line
++	tab indented line
++  new indented line
+     double indented line
+   back to single indent
+ no indent
+   indented again
+     double indent again
+-      triple indent
++      hi there mate
+   back to single
+ last line`;
+
+    const expected = `first line
+  indented line
+	tab indented line
+  new indented line
+    double indented line
+  back to single indent
+no indent
+  indented again
+    double indent again
+      hi there mate
+  back to single
+last line`;
+
+    const result = await strategy.applyDiff(original, diff);
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.content).toBe(expected);
+    }
+  });
+
+  it('should handle high level edits', async () => {
+
+    const original = `def factorial(n):
+    if n == 0:
+        return 1
+    else:
+        return n * factorial(n-1)`
+    const diff = `@@ ... @@
+-def factorial(n):
+-    if n == 0:
+-        return 1
+-    else:
+-        return n * factorial(n-1)
++def factorial(number):
++    if number == 0:
++        return 1
++    else:
++        return number * factorial(number-1)`
+
+const expected = `def factorial(number):
+    if number == 0:
+        return 1
+    else:
+        return number * factorial(number-1)`
+
+    const result = await strategy.applyDiff(original, diff);
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.content).toBe(expected);
+    }
+  });
+
+  it('it should handle very complex edits', async () => {
+    const original = `//Initialize the array that will hold the primes
+var primeArray = [];
+/*Write a function that checks for primeness and
+ pushes those values to t*he array*/
+function PrimeCheck(candidate){
+  isPrime = true;
+  for(var i = 2; i < candidate && isPrime; i++){
+    if(candidate%i === 0){
+      isPrime = false;
+    } else {
+      isPrime = true;
+    }
+  }
+  if(isPrime){
+    primeArray.push(candidate);
+  }
+  return primeArray;
+}
+/*Write the code that runs the above until the
+ l ength of the array equa*ls the number of primes
+ desired*/
+
+var numPrimes = prompt("How many primes?");
+
+//Display the finished array of primes
+
+//for loop starting at 2 as that is the lowest prime number keep going until the array is as long as we requested
+for (var i = 2; primeArray.length < numPrimes; i++) {
+  PrimeCheck(i); //
+}
+console.log(primeArray);
+`
+
+    const diff = `--- test_diff.js
++++ test_diff.js
+@@ ... @@
+-//Initialize the array that will hold the primes
+ var primeArray = [];
+-/*Write a function that checks for primeness and
+- pushes those values to t*he array*/
+ function PrimeCheck(candidate){
+   isPrime = true;
+   for(var i = 2; i < candidate && isPrime; i++){
+@@ ... @@
+   return primeArray;
+ }
+-/*Write the code that runs the above until the
+-  l ength of the array equa*ls the number of primes
+-  desired*/
+ 
+ var numPrimes = prompt("How many primes?");
+ 
+-//Display the finished array of primes
+-
+-//for loop starting at 2 as that is the lowest prime number keep going until the array is as long as we requested
+ for (var i = 2; primeArray.length < numPrimes; i++) {
+-  PrimeCheck(i); //
++  PrimeCheck(i);
+ }
+ console.log(primeArray);`
+
+    const expected = `var primeArray = [];
+function PrimeCheck(candidate){
+  isPrime = true;
+  for(var i = 2; i < candidate && isPrime; i++){
+    if(candidate%i === 0){
+      isPrime = false;
+    } else {
+      isPrime = true;
+    }
+  }
+  if(isPrime){
+    primeArray.push(candidate);
+  }
+  return primeArray;
+}
+
+var numPrimes = prompt("How many primes?");
+
+for (var i = 2; primeArray.length < numPrimes; i++) {
+  PrimeCheck(i);
+}
+console.log(primeArray);
+`
+ 
+
+    const result = await strategy.applyDiff(original, diff);
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.content).toBe(expected);
+    }
+  });
+});
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