New AsyncBase class, refs #878

tests/test_asyncdi.py

@@ -0,0 +1,80 @@
+import asyncio
+from datasette.utils.asyncdi import AsyncBase
+import pytest
+from random import random
+
+
+class Simple(AsyncBase):
+    def __init__(self):
+        self.log = []
+
+    async def two(self):
+        self.log.append("two")
+
+    async def one(self, two):
+        self.log.append("one")
+        return self.log
+
+
+class Complex(AsyncBase):
+    def __init__(self):
+        self.log = []
+
+    async def d(self):
+        await asyncio.sleep(random() * 0.1)
+        self.log.append("d")
+
+    async def c(self):
+        await asyncio.sleep(random() * 0.1)
+        self.log.append("c")
+
+    async def b(self, c, d):
+        self.log.append("b")
+
+    async def a(self, b, c):
+        self.log.append("a")
+
+    async def go(self, a):
+        self.log.append("go")
+        return self.log
+
+
+class WithParameters(AsyncBase):
+    async def go(self, calc1, calc2, param1):
+        return param1 + calc1 + calc2
+
+    async def calc1(self):
+        return 5
+
+    async def calc2(self):
+        return 6
+
+
+@pytest.mark.asyncio
+async def test_simple():
+    assert await Simple().one() == ["two", "one"]
+
+
+@pytest.mark.asyncio
+async def test_complex():
+    result = await Complex().go()
+    # 'c' should only be called once
+    assert tuple(result) in (
+        # c and d could happen in either order
+        ("c", "d", "b", "a", "go"),
+        ("d", "c", "b", "a", "go"),
+    )
+
+
+@pytest.mark.asyncio
+async def test_with_parameters():
+    result = await WithParameters().go(param1=4)
+    assert result == 15
+
+    # Should throw an error if that parameter is missing
+    with pytest.raises(AssertionError) as e:
+        await WithParameters().go()
+        assert e.args[0] == (
+            "The following DI parameters could not be "
+            "found in the registry: ['param1']"
+        )