diff --git a/.gitea/workflows/test.yml b/.gitea/workflows/test.yml
index c1a0d32..f80c6de 100644
--- a/.gitea/workflows/test.yml
+++ b/.gitea/workflows/test.yml
@@ -20,5 +20,7 @@ jobs:
         # Add files into /Tests/bin/Debug/net7.0 and create thisfileexist.txt
         run: |
          echo "incredible file" > /workspace/EPITA-TP-PROG/B2B-Training/Tests/bin/Debug/net7.0/thisfileexist.txt
+         echo -n "Bonjour,\nCeci est un message de test.\nJ'espere que vous allez reussir vos exams :D." > /workspace/EPITA-TP-PROG/B2B-Training/Tests/bin/Debug/net7.0/MyReplaceTestFile.txt
+         echo "✅ Finished"
       - name: "✅ Test"
         run: dotnet test
\ No newline at end of file
diff --git a/Stream/.DS_Store b/Stream/.DS_Store
new file mode 100644
index 0000000..42451df
Binary files /dev/null and b/Stream/.DS_Store differ
diff --git a/Stream/Program.cs b/Stream/Program.cs
index e5dff12..0f5d5ee 100644
--- a/Stream/Program.cs
+++ b/Stream/Program.cs
@@ -1,3 +1,3 @@
 // See https://aka.ms/new-console-template for more information
 
-Console.WriteLine("Hello, World!");
\ No newline at end of file
+Stream.Stream.MyReplace("test.txt", 'u', 'a');
\ No newline at end of file
diff --git a/Stream/Stream.cs b/Stream/Stream.cs
index 603bc08..6bf7b6a 100644
--- a/Stream/Stream.cs
+++ b/Stream/Stream.cs
@@ -7,4 +7,38 @@ public class Stream
     {
         return File.Exists(path);
     }
+
+    public static void MyReplace(string path, char toReplace, char replace)
+    {
+        string preResult = String.Empty;
+        string result = String.Empty;
+        try
+        {
+            using (StreamReader sr = new StreamReader(path))
+            {
+                preResult = sr.ReadToEnd();
+            }
+
+            foreach (var chara in preResult)
+            {
+                if (chara == toReplace)
+                {
+                    result += replace;
+                }
+                else
+                {
+                    result += chara;
+                }
+            }
+
+            using (StreamWriter sw = new StreamWriter(path))
+            {
+                sw.WriteLine(result);
+            }
+        }
+        catch (Exception)
+        {
+            throw new ArgumentException("Error");
+        }
+    }
 }
\ No newline at end of file
diff --git a/Tests/Stream/StreamTest.cs b/Tests/Stream/StreamTest.cs
index 89f7157..9459bc9 100644
--- a/Tests/Stream/StreamTest.cs
+++ b/Tests/Stream/StreamTest.cs
@@ -10,4 +10,13 @@ public class StreamTest
     {
         Assert.Equal(expected, global::Stream.Stream.ExistFile(filePath));
     }
+
+    [Theory]
+    [InlineData("MyReplaceTestFile.txt", 'e', 'f')]
+
+    public void MyReplaceTest(string filePath, char toReplace, char replace)
+    {
+        global::Stream.Stream.MyReplace(filePath, toReplace, replace);
+        Assert.Equal("Bonjour,\nCfci fst un mfssagf df tfst.\nJ'fspfrf quf vous allfz rfussir vos fxams :D.\n", File.ReadAllText(filePath));
+    }
 }
\ No newline at end of file