tb: Refactor out with_valids

Parametrizing a test over different methods of generating valid data
will be useful for other tests as well. Refactor it out. We have to bind
valids early in with_valids.test, otherwise we will end up binding
with_valids.valid by reference (causing all tests to use saw_valid).

Signed-off-by: Sean Anderson <seanga2@gmail.com>

tb/pcs.py

@@ -268,6 +268,4 @@ async def test_rx(pcs, valids):
     for _ in range(10):
         assert [0x5, 0x5] == await alist(mii_recv_packet(pcs))
 
-rx_tests = TestFactory(test_rx)
-rx_tests.add_option('valids', (one_valid, two_valid, rand_valid, saw_valid()))
-rx_tests.generate_tests()
+with_valids(globals(), test_rx)

tb/util.py

@@ -89,6 +89,15 @@ class saw_valid:
             self.last = 0
         return self.last
 
+def with_valids(g, f):
+    for valids in (one_valid, two_valid, rand_valid, saw_valid()):
+        async def test(*args, valids=valids, **kwargs):
+            await f(*args, valids=valids, **kwargs)
+        test.__name__ = f"{f.__name__}_{valids.__qualname__}"
+        test.__qualname__ = f"{f.__qualname__}_{valids.__qualname__}"
+        test.valids = valids
+        g[test.__name__] = cocotb.test()(test)
+
 async def send_recovered_bits(clk, data, valid, bits, valids):
     bits = iter(bits)
     await FallingEdge(clk)