diff --git a/scripts/test_diff_analyzer.py b/scripts/test_diff_analyzer.py
new file mode 100644
index 0000000..636b5a2
--- /dev/null
+++ b/scripts/test_diff_analyzer.py
@@ -0,0 +1,189 @@
+#!/usr/bin/env python3
+"""Tests for scripts/diff_analyzer.py — 10 tests."""
+
+import sys
+import os
+sys.path.insert(0, os.path.dirname(__file__) or ".")
+
+import importlib.util
+spec = importlib.util.spec_from_file_location("da", os.path.join(os.path.dirname(__file__) or ".", "diff_analyzer.py"))
+mod = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(mod)
+DiffAnalyzer = mod.DiffAnalyzer
+ChangeCategory = mod.ChangeCategory
+
+
+SAMPLE_ADD = """diff --git a/new.py b/new.py
+new file mode 100644
+--- /dev/null
++++ b/new.py
+@@ -0,0 +1,3 @@
++def hello():
++    print("world")
++    return True
+"""
+
+SAMPLE_DELETE = """diff --git a/old.py b/old.py
+deleted file mode 100644
+--- a/old.py
++++ /dev/null
+@@ -1,2 +0,0 @@
+-def goodbye():
+-    pass
+"""
+
+SAMPLE_MODIFY = """diff --git a/app.py b/app.py
+--- a/app.py
++++ b/app.py
+@@ -1,3 +1,4 @@
+ def main():
+-    print("old")
++    print("new")
++    print("extra")
+     return 0
+"""
+
+SAMPLE_RENAME = """diff --git a/old_name.py b/new_name.py
+rename from old_name.py
+rename to new_name.py
+--- a/old_name.py
++++ b/new_name.py
+@@ -1,1 +1,1 @@
+-old content
++new content
+"""
+
+SAMPLE_MULTI = """diff --git a/a.py b/a.py
+--- a/a.py
++++ b/a.py
+@@ -1,1 +1,2 @@
+ existing
++added line
+diff --git b/b.py b/b.py
+new file mode 100644
+--- /dev/null
++++ b/b.py
+@@ -0,0 +1,1 @@
++new file
+"""
+
+SAMPLE_BINARY = """diff --git a/img.png b/img.png
+Binary files a/img.png and b/img.png differ
+"""
+
+
+def test_empty():
+    a = DiffAnalyzer()
+    s = a.analyze("")
+    assert s.total_files_changed == 0
+    print("PASS: test_empty")
+
+def test_addition():
+    a = DiffAnalyzer()
+    s = a.analyze(SAMPLE_ADD)
+    assert s.total_files_changed == 1
+    assert s.total_added == 3
+    assert s.total_deleted == 0
+    assert s.new_files == 1
+    assert s.files[0].hunks[0].category == ChangeCategory.ADDED
+    print("PASS: test_addition")
+
+def test_deletion():
+    a = DiffAnalyzer()
+    s = a.analyze(SAMPLE_DELETE)
+    assert s.total_deleted == 2
+    assert s.deleted_files == 1
+    assert s.files[0].hunks[0].category == ChangeCategory.DELETED
+    print("PASS: test_deletion")
+
+def test_modification():
+    a = DiffAnalyzer()
+    s = a.analyze(SAMPLE_MODIFY)
+    assert s.total_added == 2
+    assert s.total_deleted == 1
+    assert s.files[0].hunks[0].category == ChangeCategory.MODIFIED
+    print("PASS: test_modification")
+
+def test_rename():
+    a = DiffAnalyzer()
+    s = a.analyze(SAMPLE_RENAME)
+    assert s.renamed_files == 1
+    assert s.files[0].old_path == "old_name.py"
+    assert s.files[0].path == "new_name.py"
+    assert s.files[0].is_renamed == True
+    print("PASS: test_rename")
+
+def test_multiple_files():
+    a = DiffAnalyzer()
+    s = a.analyze(SAMPLE_MULTI)
+    assert s.total_files_changed == 2
+    assert s.new_files == 1
+    print("PASS: test_multiple_files")
+
+def test_binary():
+    a = DiffAnalyzer()
+    s = a.analyze(SAMPLE_BINARY)
+    assert s.binary_files == 1
+    assert s.files[0].is_binary == True
+    assert len(s.files[0].hunks) == 0
+    print("PASS: test_binary")
+
+def test_to_dict():
+    a = DiffAnalyzer()
+    s = a.analyze(SAMPLE_MODIFY)
+    d = s.to_dict()
+    assert "total_files_changed" in d
+    assert "files" in d
+    assert isinstance(d["files"], list)
+    print("PASS: test_to_dict")
+
+def test_context_only():
+    diff = """diff --git a/f.py b/f.py
+--- a/f.py
++++ b/f.py
+@@ -1,3 +1,3 @@
+ line1
+-old
++new
+ line3
+"""
+    a = DiffAnalyzer()
+    s = a.analyze(diff)
+    # Has both added and deleted = MODIFIED
+    assert s.files[0].hunks[0].category == ChangeCategory.MODIFIED
+    print("PASS: test_context_only")
+
+def test_multi_hunk():
+    diff = """diff --git a/f.py b/f.py
+--- a/f.py
++++ b/f.py
+@@ -1,1 +1,2 @@
+ existing
++first addition
+@@ -10,1 +11,2 @@
+ more
++second addition
+"""
+    a = DiffAnalyzer()
+    s = a.analyze(diff)
+    assert s.total_hunks == 2
+    assert s.total_added == 2
+    print("PASS: test_multi_hunk")
+
+
+def run_all():
+    test_empty()
+    test_addition()
+    test_deletion()
+    test_modification()
+    test_rename()
+    test_multiple_files()
+    test_binary()
+    test_to_dict()
+    test_context_only()
+    test_multi_hunk()
+    print("\nAll 10 tests passed!")
+
+
+if __name__ == "__main__":
+    run_all()