From 434c3e6e5563fda09822aa34c50543e411d2fa7a Mon Sep 17 00:00:00 2001
From: tessier <tessier@luxeys.com>
Date: Fri, 21 Mar 2025 18:22:31 +0900
Subject: [PATCH] feat(scripts): add docstring and tests

---
 diagrams/cli.py   | 11 +++++-
 tests/test_cli.py | 94 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 103 insertions(+), 2 deletions(-)
 create mode 100644 tests/test_cli.py

diff --git a/diagrams/cli.py b/diagrams/cli.py
index 22a73685..c75eb3d9 100644
--- a/diagrams/cli.py
+++ b/diagrams/cli.py
@@ -3,6 +3,14 @@ import sys
 
 
 def run() -> int:
+    """
+    Run diagrams code files in a diagrams environment.
+    Args:
+        paths: A list of paths to Python files containing diagrams code.
+
+    Returns:
+        The exit code.
+    """
     parser = argparse.ArgumentParser(
         description="Run diagrams code files in a diagrams environment.",
     )
@@ -16,8 +24,7 @@ def run() -> int:
     args = parser.parse_args()
 
     for path in args.paths:
-        print(path)
-        with open(path) as f:
+        with open(path, encoding='utf-8') as f:
             exec(f.read())
 
     return 0
diff --git a/tests/test_cli.py b/tests/test_cli.py
new file mode 100644
index 00000000..3b3e9750
--- /dev/null
+++ b/tests/test_cli.py
@@ -0,0 +1,94 @@
+import os
+import unittest
+from unittest.mock import patch, mock_open
+from io import StringIO
+
+from diagrams.cli import run
+
+class CliTest(unittest.TestCase):
+    def setUp(self):
+        self.test_file = "test_diagram.py"
+        # dummy content for the test file
+        self.test_content_1 = """
+from diagrams import Diagram
+with Diagram(name="Test", show=False):
+    pass
+"""
+        # content from getting started examples with utf-8
+        # only support the installed fonts defined in Dockerfile
+        self.test_content_2 = """
+from diagrams import Diagram
+from diagrams.aws.compute import EC2
+from diagrams.aws.database import RDS
+from diagrams.aws.network import ELB
+
+with Diagram("test_2", show=False, direction="TB"):
+    ELB("lb") >> [EC2("ワーカー１"),
+                  EC2("작업자 2를"),
+                  EC2("робітник 3"),
+                  EC2("worker4"),
+                  EC2("työntekijä 4")] >> RDS("events")
+"""
+    def tearDown(self):
+        try:
+            os.remove("test.png")
+        except FileNotFoundError:
+            pass
+
+    def test_run_with_valid_file(self):
+        # write the test file
+        with open(self.test_file, "w") as f:
+            f.write(self.test_content_1)
+        with patch("sys.argv", ["diagrams", self.test_file]):
+            exit_code = run()
+            self.assertEqual(exit_code, 0)
+        try:
+            os.remove(self.test_file)
+        except FileNotFoundError:
+            pass
+
+
+    def test_run_with_multiple_files(self):
+
+        multiple_files = ["file1.py", "file2.py"]
+
+        # write the code files
+        with open("file1.py", "w") as f:
+            f.write(self.test_content_1)
+        with open("file2.py", "w") as f:
+            f.write(self.test_content_2)
+
+        with patch("sys.argv", ["diagrams"] + multiple_files):
+            exit_code = run()
+            self.assertEqual(exit_code, 0)
+
+        # cleanup code file
+        for one_file in multiple_files:
+            try:
+                os.remove(one_file)
+            except FileNotFoundError:
+                pass
+        # cleanup generated image
+        try:
+            os.remove("test_2.png")
+        except FileNotFoundError:
+            pass
+
+    def test_run_with_no_arguments(self):
+        with patch("sys.argv", ["diagrams"]):
+            with patch("sys.stderr", new=StringIO()) as fake_stderr:
+                with self.assertRaises(SystemExit):
+                    run()
+                self.assertIn("the following arguments are required: path", fake_stderr.getvalue())
+
+    def test_run_with_nonexistent_file(self):
+        with patch("sys.argv", ["diagrams", "nonexistent.py"]):
+            with self.assertRaises(FileNotFoundError):
+                run()
+
+    def test_run_with_invalid_python_code(self):
+        invalid_content = "this is not valid python code"
+        with patch("builtins.open", mock_open(read_data=invalid_content)):
+            with patch("sys.argv", ["diagrams", self.test_file]):
+                with self.assertRaises(SyntaxError):
+                    run()