diff --git a/src/backend/Assembly_test.zig b/src/backend/Assembly_test.zig
new file mode 100644
index 0000000000000000000000000000000000000000..4457e1466a2042cedd30fcd85a70b9a48489b096
--- /dev/null
+++ b/src/backend/Assembly_test.zig
@@ -0,0 +1,62 @@
+const std = @import("std");
+const Assembly = @import("Assembly.zig").Assembly;
+
+test "writeToAllFile - empty data and empty text" {
+    const assembly = Assembly{
+        .data = &.{},
+        .text = &.{},
+    };
+    var buffer: [1024]u8 = undefined;
+    var fbs = std.io.FixedBufferStream(&buffer);
+    const file = try std.fs.File.openWriter(fbs.writer());
+    try assembly.writeToAllFile(file);
+    try std.testing.expectEqualStrings("", fbs.getWritten());
+}
+
+test "writeToAllFile - only data, no text" {
+    const assembly = Assembly{
+        .data = "hello data",
+        .text = &.{};
+    };
+    var buffer: [1024]u8 = undefined;
+    var fbs = std.io.FixedBufferStream(&buffer);
+    const file = try std.fs.File.openWriter(fbs.writer());
+    try assembly.writeToAllFile(file);
+    try std.testing.expectEqualStrings("hello data", fbs.getWritten());
+}
+
+test "writeToAllFile - only text, no data" {
+    const assembly = Assembly{
+        .data = &.{},
+        .text = "hello text",
+    };
+    var buffer: [1024]u8 = undefined;
+    var fbs = std.io.FixedBufferStream(&buffer);
+    const file = try std.fs.File.openWriter(fbs.writer());
+    try assembly.writeToAllFile(file);
+    try std.testing.expectEqualStrings("hello text", fbs.getWritten());
+}
+
+test "writeToAllFile - both data and text" {
+    const assembly = Assembly{
+        .data = "data content",
+        .text = " text content",
+    };
+    var buffer: [1024]u8 = undefined;
+    var fbs = std.io.FixedBufferStream(&buffer);
+    const file = try std.fs.File.openWriter(fbs.writer());
+    try assembly.writeToAllFile(file);
+    try std.testing.expectEqualStrings("data content text content", fbs.getWritten());
+}
+
+test "writeToAllFile - invalid file descriptor" {
+    const assembly = Assembly{
+        .data = "test data",
+        .text = "test text",
+    };
+    const invalid_file = std.fs.File{
+        .handle = -1,
+        .mode = .read_write,
+    };
+    try std.testing.expectError(error.InputOutput, assembly.writeToAllFile(invalid_file));
+}