tests: Add some tests for urandom module.

tests/extmod/urandom_basic.py

@@ -0,0 +1,19 @@
+try:
+    import urandom as random
+except ImportError:
+    import random
+
+# check getrandbits returns a value within the bit range
+for b in (1, 2, 3, 4, 16, 32):
+    for i in range(50):
+        assert random.getrandbits(b) < (1 << b)
+
+# check that seed(0) gives a non-zero value
+random.seed(0)
+print(random.getrandbits(16) != 0)
+
+# check that PRNG is repeatable
+random.seed(1)
+r = random.getrandbits(16)
+random.seed(1)
+print(random.getrandbits(16) == r)

tests/extmod/urandom_extra.py

@@ -0,0 +1,39 @@
+try:
+    import urandom as random
+except ImportError:
+    import random
+
+try:
+    random.randint
+except AttributeError:
+    import sys
+    print('SKIP')
+    sys.exit(1)
+
+print('randrange')
+for i in range(50):
+    assert 0 <= random.randrange(4) < 4
+    assert 2 <= random.randrange(2, 6) < 6
+    assert -2 <= random.randrange(-2, 2) < 2
+    assert random.randrange(1, 9, 2) in (1, 3, 5, 7)
+
+print('randint')
+for i in range(50):
+    assert 0 <= random.randint(0, 4) <= 4
+    assert 2 <= random.randint(2, 6) <= 6
+    assert -2 <= random.randint(-2, 2) <= 2
+
+print('choice')
+lst = [1, 2, 5, 6]
+for i in range(50):
+    assert random.choice(lst) in lst
+
+print('random')
+for i in range(50):
+    assert 0 <= random.random() < 1
+
+print('uniform')
+for i in range(50):
+    assert 0 <= random.uniform(0, 4) <= 4
+    assert 2 <= random.uniform(2, 6) <= 6
+    assert -2 <= random.uniform(-2, 2) <= 2