Add print to file with filename (#18)

README.md

@@ -164,6 +164,18 @@ with open("watch.log", "w") as f:
 a = 1
 ```
 
+Or you could just give a filename to ``watch``. It will append to the file.
+
+```python
+watch(a, file="watch.log")
+```
+
+Use config if you want to make it global
+
+```python
+watch.config(file="watch.log")
+```
+
 ### alias
 
 You can give an alias to a monitored variable, so you can unwatch it anywhere. And the alias will be printed instead of the variable name

src/watchpoints/watch_print.py

@@ -75,7 +75,15 @@ def getsourceline(self, exec_info):
             return "unable to locate the source"
 
     def printer(self, obj):
-        if type(obj) is str:
-            print(obj, file=self.file)
+
+        def do_print(obj, stream):
+            if type(obj) is str:
+                print(obj, file=stream)
+            else:
+                pprint.pprint(obj, stream=stream)
+
+        if isinstance(self.file, str):
+            with open(self.file, "a") as f:
+                do_print(obj, f)
         else:
-            pprint.pprint(obj, stream=self.file)
+            do_print(obj, self.file)

tests/test_watch.py

@@ -4,6 +4,7 @@
 
 from contextlib import redirect_stdout
 import io
+import os
 import sys
 import unittest
 from watchpoints import watch, unwatch
@@ -235,7 +236,7 @@ def test_stack_limit_local(self):
             unwatch()
             self.assertEqual(s.getvalue().count("> "), 1)
 
-    def test_write_to_file(self):
+    def test_write_to_file_stream(self):
         f = open("tmp_test.log", "w")
         a = [1, 2, 3]
         watch(a, file=f, stack_limit=1)
@@ -244,4 +245,15 @@ def test_write_to_file(self):
         f.close()
         with open("tmp_test.log") as f:
             data = f.read()
+        os.remove("tmp_test.log")
         self.assertEqual(data.count("> "), 1)
+
+    def test_write_to_file(self):
+        a = [1, 2, 3]
+        watch(a, file="tmp_test.log")
+        a[0] = 2
+        unwatch()
+        with open("tmp_test.log") as f:
+            data = f.read()
+        os.remove("tmp_test.log")
+        self.assertIn("a[0] = 2", data)

tests/test_watch_print.py

@@ -11,14 +11,16 @@
 from watchpoints.watch_print import WatchPrint
 
 
+class Elem:
+    def __init__(self):
+        self.alias = None
+        self.default_alias = "a"
+        self.prev_obj = ""
+        self.obj = ""
+
+
 class TestWatchPrint(unittest.TestCase):
     def test_basic(self):
-        class Elem:
-            def __init__(self):
-                self.alias = None
-                self.default_alias = "a"
-                self.prev_obj = ""
-                self.obj = ""
         s = io.StringIO()
         with redirect_stdout(s):
             wp = WatchPrint(file=sys.stdout)
@@ -44,3 +46,12 @@ def test_getsourceline(self):
 
         line = wp.getsourceline((None, "file/not/exist", 100))
         self.assertEqual(line, "unable to locate the source")
+
+    def test_print_to_file(self):
+        wp = WatchPrint(file="tmp_test.log")
+        wp(inspect.currentframe(), Elem(), ("function", "filename", "c"))
+        with open("tmp_test.log") as f:
+            data = f.read()
+        os.remove("tmp_test.log")
+        self.assertIn("function", data)
+        self.assertIn("filename", data)