[config] Implements "Exclusive" context processor allowing to ask for an exclusive usage of a service while in a transformation.

tests/config/test_services.py

@@ -0,0 +1,96 @@
+import threading
+import time
+
+import pytest
+
+from bonobo.config import Configurable, Container, Exclusive, Service
+from bonobo.config.services import validate_service_name
+
+
+class PrinterInterface():
+    def print(self, *args):
+        raise NotImplementedError()
+
+
+class ConcretePrinter(PrinterInterface):
+    def __init__(self, prefix):
+        self.prefix = prefix
+
+    def print(self, *args):
+        return ';'.join((self.prefix, *args))
+
+
+SERVICES = Container(
+    printer0=ConcretePrinter(prefix='0'),
+    printer1=ConcretePrinter(prefix='1'),
+)
+
+
+class MyServiceDependantConfigurable(Configurable):
+    printer = Service(
+        PrinterInterface,
+    )
+
+    def __call__(self, printer: PrinterInterface, *args):
+        return printer.print(*args)
+
+
+def test_service_name_validator():
+    assert validate_service_name('foo') == 'foo'
+    assert validate_service_name('foo.bar') == 'foo.bar'
+    assert validate_service_name('Foo') == 'Foo'
+    assert validate_service_name('Foo.Bar') == 'Foo.Bar'
+    assert validate_service_name('Foo.a0') == 'Foo.a0'
+
+    with pytest.raises(ValueError):
+        validate_service_name('foo.0')
+
+    with pytest.raises(ValueError):
+        validate_service_name('0.foo')
+
+
+def test_service_dependency():
+    o = MyServiceDependantConfigurable(printer='printer0')
+
+    assert o(SERVICES.get('printer0'), 'foo', 'bar') == '0;foo;bar'
+    assert o(SERVICES.get('printer1'), 'bar', 'baz') == '1;bar;baz'
+    assert o(*SERVICES.args_for(o), 'foo', 'bar') == '0;foo;bar'
+
+
+def test_service_dependency_unavailable():
+    o = MyServiceDependantConfigurable(printer='printer2')
+    with pytest.raises(KeyError):
+        SERVICES.args_for(o)
+
+
+class VCR:
+    def __init__(self):
+        self.tape = []
+
+    def append(self, x):
+        return self.tape.append(x)
+
+
+def test_exclusive():
+    vcr = VCR()
+    vcr.append('hello')
+
+    def record(prefix, vcr=vcr):
+        with Exclusive(vcr):
+            for i in range(5):
+                vcr.append(' '.join((prefix, str(i))))
+                time.sleep(0.05)
+
+    threads = [threading.Thread(target=record, args=(str(i), )) for i in range(5)]
+
+    for thread in threads:
+        thread.start()
+        time.sleep(0.01)  # this is not good practice, how to test this without sleeping ?? XXX
+
+    for thread in threads:
+        thread.join()
+
+    assert vcr.tape == [
+        'hello', '0 0', '0 1', '0 2', '0 3', '0 4', '1 0', '1 1', '1 2', '1 3', '1 4', '2 0', '2 1', '2 2', '2 3',
+        '2 4', '3 0', '3 1', '3 2', '3 3', '3 4', '4 0', '4 1', '4 2', '4 3', '4 4'
+    ]