Add factory method for log events to assert on for better readability (…

…#23)

* Add factory method for log events to assert on for better readability

---------

Co-authored-by: Logi <[email protected]>
Co-authored-by: wim glenn <[email protected]>

README.rst

@@ -81,6 +81,15 @@ Then your test suite might use assertions such as shown below:
            {"event": "processing", "level": "debug", "spline": 2},
            {"event": "reticulated splines", "level": "info", "n_splines": 3},
        ]
+       
+       # can use friendly factory methods for the events to assert on
+       assert log.events == [
+           log.info("reticulating splines"),
+           log.debug("processing", spline=0),
+           log.debug("processing", spline=1),
+           log.debug("processing", spline=2),
+           log.info("reticulated splines", n_splines=3),
+       ]
 
        # can use membership to check for a single event's data
        assert {"event": "reticulating splines", "level": "info"} in log.events

pytest_structlog.py

@@ -1,3 +1,4 @@
+import logging
 import os
 
 import pytest
@@ -40,6 +41,13 @@ def __lt__(self, other):
 absent = object()
 
 
+def level_to_name(level):
+    """Given the name or number for a log-level, return the lower-case level name."""
+    if isinstance(level, str):
+        return level.lower()
+    return logging.getLevelName(level).lower()
+
+
 def is_submap(d1, d2):
     """is every pair from d1 also in d2? (unique and order insensitive)"""
     return all(d2.get(k, absent) == v for k, v in d1.items())
@@ -64,6 +72,30 @@ def has(self, message, **context):
         context["event"] = message
         return any(is_submap(context, e) for e in self.events)
 
+    def log(self, level, event, **kw):
+        """Create log event to assert against"""
+        return dict(level=level_to_name(level), event=event, **kw)
+
+    def debug(self, event, **kw):
+        """Create debug-level log event to assert against"""
+        return self.log(logging.DEBUG, event, **kw)
+
+    def info(self, event, **kw):
+        """Create info-level log event to assert against"""
+        return self.log(logging.INFO, event, **kw)
+
+    def warning(self, event, **kw):
+        """Create warning-level log event to assert against"""
+        return self.log(logging.WARNING, event, **kw)
+
+    def error(self, event, **kw):
+        """Create error-level log event to assert against"""
+        return self.log(logging.ERROR, event, **kw)
+
+    def critical(self, event, **kw):
+        """Create critical-level log event to assert against"""
+        return self.log(logging.CRITICAL, event, **kw)
+
 
 def no_op(*args, **kwargs):
     pass

tests/test_log.py

@@ -1,3 +1,6 @@
+import logging
+
+import pytest
 import structlog
 
 
@@ -140,3 +143,33 @@ def test_dupes(log):
         {"event": "a", "level": "info"},
         {"event": "b", "level": "info"},
     ]
+
+
+def test_event_factories(log):
+    assert log.debug("debug-level", extra=True) == {"event": "debug-level", "level": "debug", "extra": True}
+    assert log.info("info-level", more="yes") == {"event": "info-level", "level": "info", "more": "yes"}
+    assert log.warning("warning-level", another=42) == {"event": "warning-level", "level": "warning", "another": 42}
+    assert log.error("error-level", added=1) == {"event": "error-level", "level": "error", "added": 1}
+    assert log.critical("crit-level", above="beyond") == {"event": "crit-level", "level": "critical", "above": "beyond"}
+
+
+@pytest.mark.parametrize(
+    "level, name",
+    [
+        (logging.DEBUG, "debug"),
+        (logging.INFO, "info"),
+        (logging.WARNING, "warning"),
+        (logging.ERROR, "error"),
+        (logging.CRITICAL, "critical"),
+    ],
+)
+def test_dynamic_event_factory(log, level, name):
+    expected = {"event": "dynamic-level", "level": name, "other": 42}
+
+    assert log.log(level, "dynamic-level", other=42) == expected
+    assert log.log(name, "dynamic-level", other=42) == expected
+    assert log.log(name.upper(), "dynamic-level", other=42) == expected
+
+
+def test_event_factory__bad_level_number(log):
+    assert log.log(1234, "text") == {'event': 'text', 'level': 'level 1234'}