Move DD code into its own directory (#6)

reference/tests/test_pin.py

@@ -0,0 +1,192 @@
+from unittest import TestCase
+
+import pytest
+
+from ddtrace import Pin
+
+
+class PinTestCase(TestCase):
+    """TestCase for the `Pin` object that is used when an object is wrapped
+    with our tracing functionalities.
+    """
+    def setUp(self):
+        # define a simple class object
+        class Obj(object):
+            pass
+
+        self.Obj = Obj
+
+    def test_pin(self):
+        # ensure a Pin can be attached to an instance
+        obj = self.Obj()
+        pin = Pin(service='metrics')
+        pin.onto(obj)
+
+        got = Pin.get_from(obj)
+        assert got.service == pin.service
+        assert got is pin
+
+    def test_pin_find(self):
+        # ensure Pin will find the first available pin
+
+        # Override service
+        obj_a = self.Obj()
+        pin = Pin(service='service-a')
+        pin.onto(obj_a)
+
+        # Override service
+        obj_b = self.Obj()
+        pin = Pin(service='service-b')
+        pin.onto(obj_b)
+
+        # No Pin set
+        obj_c = self.Obj()
+
+        # We find the first pin (obj_b)
+        pin = Pin._find(obj_c, obj_b, obj_a)
+        assert pin is not None
+        assert pin.service == 'service-b'
+
+        # We find the first pin (obj_a)
+        pin = Pin._find(obj_a, obj_b, obj_c)
+        assert pin is not None
+        assert pin.service == 'service-a'
+
+        # We don't find a pin if none is there
+        pin = Pin._find(obj_c, obj_c, obj_c)
+        assert pin is None
+
+    def test_cant_pin_with_slots(self):
+        # ensure a Pin can't be attached if the __slots__ is defined
+        class Obj(object):
+            __slots__ = ['value']
+
+        obj = Obj()
+        obj.value = 1
+
+        Pin(service='metrics').onto(obj)
+        got = Pin.get_from(obj)
+        assert got is None
+
+    def test_cant_modify(self):
+        # ensure a Pin is immutable once initialized
+        pin = Pin(service='metrics')
+        with pytest.raises(AttributeError):
+            pin.service = 'intake'
+
+    def test_copy(self):
+        # ensure a Pin is copied when using the clone methods
+        p1 = Pin(service='metrics', app='flask', tags={'key': 'value'})
+        p2 = p1.clone(service='intake')
+        # values are the same
+        assert p1.service == 'metrics'
+        assert p2.service == 'intake'
+        assert p1.app == 'flask'
+        assert p2.app == 'flask'
+        # but it's a copy
+        assert p1.tags is not p2.tags
+        assert p1._config is not p2._config
+        # of almost everything
+        assert p1.tracer is p2.tracer
+
+    def test_none(self):
+        # ensure get_from returns None if a Pin is not available
+        assert Pin.get_from(None) is None
+
+    def test_repr(self):
+        # ensure the service name is in the string representation of the Pin
+        pin = Pin(service='metrics')
+        assert 'metrics' in str(pin)
+
+    def test_override(self):
+        # ensure Override works for an instance object
+        class A(object):
+            pass
+
+        Pin(service='metrics', app='flask').onto(A)
+        a = A()
+        Pin.override(a, app='django')
+        assert Pin.get_from(a).app == 'django'
+        assert Pin.get_from(a).service == 'metrics'
+
+        b = A()
+        assert Pin.get_from(b).app == 'flask'
+        assert Pin.get_from(b).service == 'metrics'
+
+    def test_override_missing(self):
+        # ensure overriding an instance doesn't override the Class
+        class A(object):
+            pass
+
+        a = A()
+        assert Pin.get_from(a) is None
+        Pin.override(a, service='metrics')
+        assert Pin.get_from(a).service == 'metrics'
+
+        b = A()
+        assert Pin.get_from(b) is None
+
+    def test_pin_config(self):
+        # ensure `Pin` has a configuration object that can be modified
+        obj = self.Obj()
+        Pin.override(obj, service='metrics')
+        pin = Pin.get_from(obj)
+        assert pin._config is not None
+        pin._config['distributed_tracing'] = True
+        assert pin._config['distributed_tracing'] is True
+
+    def test_pin_config_is_a_copy(self):
+        # ensure that when a `Pin` is cloned, the config is a copy
+        obj = self.Obj()
+        Pin.override(obj, service='metrics')
+        p1 = Pin.get_from(obj)
+        assert p1._config is not None
+        p1._config['distributed_tracing'] = True
+
+        Pin.override(obj, service='intake')
+        p2 = Pin.get_from(obj)
+        assert p2._config is not None
+        p2._config['distributed_tracing'] = False
+
+        assert p1._config['distributed_tracing'] is True
+        assert p2._config['distributed_tracing'] is False
+
+    def test_pin_does_not_override_global(self):
+        # ensure that when a `Pin` is created from a class, the specific
+        # instance doesn't override the global one
+        class A(object):
+            pass
+
+        Pin.override(A, service='metrics')
+        global_pin = Pin.get_from(A)
+        global_pin._config['distributed_tracing'] = True
+
+        a = A()
+        pin = Pin.get_from(a)
+        assert pin is not None
+        assert pin._config['distributed_tracing'] is True
+        pin._config['distributed_tracing'] = False
+
+        assert global_pin._config['distributed_tracing'] is True
+        assert pin._config['distributed_tracing'] is False
+
+    def test_pin_does_not_override_global_with_new_instance(self):
+        # ensure that when a `Pin` is created from a class, the specific
+        # instance doesn't override the global one, even if only the
+        # `onto()` API has been used
+        class A(object):
+            pass
+
+        pin = Pin(service='metrics')
+        pin.onto(A)
+        global_pin = Pin.get_from(A)
+        global_pin._config['distributed_tracing'] = True
+
+        a = A()
+        pin = Pin.get_from(a)
+        assert pin is not None
+        assert pin._config['distributed_tracing'] is True
+        pin._config['distributed_tracing'] = False
+
+        assert global_pin._config['distributed_tracing'] is True
+        assert pin._config['distributed_tracing'] is False