add unittests for Constant

migen/test/test_constant.py

@@ -0,0 +1,28 @@
+import unittest
+
+from migen.fhdl.std import *
+from migen.test.support import SimCase, SimBench
+
+
+class ConstantCase(SimCase, unittest.TestCase):
+    class TestBench(SimBench):
+        def __init__(self):
+            self.sigs = [
+                (Signal(3), Constant(0), 0),
+                (Signal(3), Constant(5), 5),
+                (Signal(3), Constant(1, 2), 1),
+                (Signal(3), Constant(-1, 7), 7),
+                (Signal(3), Constant(0b10101)[:3], 0b101),
+                (Signal(3), Constant(0b10101)[1:4], 0b10),
+            ]
+            self.comb += [a.eq(b) for a, b, c in self.sigs]
+
+    def test_comparisons(self):
+        def cb(tb, tbp):
+            for s, l, v in tb.sigs:
+                s = tbp.simulator.rd(s)
+                self.assertEqual(
+                    s, int(v),
+                    "got {}, want {} from literal {}".format(
+                        s, v, l))
+        self.run_with(cb, 1)