proper tests for logs with colour

src/ophyd_async/core/log.py

@@ -1,4 +1,4 @@
-# The LogFormatter is adapted light from tornado, which is licensed under
+# The LogFormatter is adapted light from tornado, which is licensed unders
 # Apache 2.0. See other_licenses/ in the repository directory.
 
 import logging
@@ -106,7 +106,7 @@ def __init__(
 
         self._colors = {}
         if color and _stderr_supports_color():
-            if curses is not None:
+            if "curses" in sys.modules:
                 # The curses module has some str/bytes confusion in
                 # python3.  Until version 3.2.3, most methods return
                 # bytes, but only accept strings.  In addition, we want to

tests/core/test_log.py

@@ -42,6 +42,29 @@ def test_logger_adapter_ophyd_async_device():
     assert log_buffer.getvalue().endswith("[test_device] here is a warning\n")
 
 
+def test_formatter_with_colour():
+    log_buffer = io.StringIO()
+    log_stream = logging.StreamHandler(stream=log_buffer)
+    with (
+        patch("ophyd_async.core.log._stderr_supports_color", return_value=True),
+        patch("curses.tigetstr", return_value=bytes(4)),
+        patch("curses.tparm", return_value=bytes(4)),
+    ):
+        log_stream.setFormatter(log.LogFormatter())
+
+
+def test_formatter_with_colour_no_curses(monkeypatch):
+    log_buffer = io.StringIO()
+    log_stream = logging.StreamHandler(stream=log_buffer)
+    with (
+        patch("ophyd_async.core.log._stderr_supports_color", return_value=True),
+        patch("curses.tigetstr", return_value=bytes(4)),
+        patch("curses.tparm", return_value=bytes(4)),
+    ):
+        monkeypatch.delitem(sys.modules, "curses", raising=False)
+        log_stream.setFormatter(log.LogFormatter())
+
+
 def test_stderr_supports_color_not_atty():
     with patch("sys.stderr.isatty", return_value=False):
         assert not _stderr_supports_color()