py: Fix build error when float disabled; add test for divmod.

py/builtin.c

@@ -247,7 +247,9 @@ STATIC mp_obj_t mp_builtin_divmod(mp_obj_t o1_in, mp_obj_t o2_in) {
         mp_int_t i1 = MP_OBJ_SMALL_INT_VALUE(o1_in);
         mp_int_t i2 = MP_OBJ_SMALL_INT_VALUE(o2_in);
         if (i2 == 0) {
+            #if MICROPY_PY_BUILTINS_FLOAT
             zero_division_error:
+            #endif
             nlr_raise(mp_obj_new_exception_msg(&mp_type_ZeroDivisionError, "division by zero"));
         }
         mp_obj_t args[2];

tests/float/float_divmod.py

@@ -0,0 +1,25 @@
+# test floating point floor divide and modulus
+# it has some tricky corner cases
+
+def test(x, y):
+    div, mod = divmod(x, y)
+    print('%.8f %.8f %.8f %.8f' % (x // y, x % y, div, mod))
+    print(div == x // y, mod == x % y, abs(div * y + mod - x) < 1e-15)
+
+test(1.23456, 0.7)
+test(-1.23456, 0.7)
+test(1.23456, -0.7)
+test(-1.23456, -0.7)
+
+a = 1.23456
+b = 0.7
+test(a, b)
+test(a, -b)
+test(-a, b)
+test(-a, -b)
+
+for i in range(25):
+    x = (i - 12.5) / 6
+    for j in range(25):
+        y = (j - 12.5) / 6
+        test(x, y)

tests/float/float_divmod_relaxed.py

@@ -0,0 +1,27 @@
+# test floating point floor divide and modulus
+# it has some tricky corner cases
+
+# pyboard has 32-bit floating point and gives different (but still
+# correct) answers for certain combinations of divmod arguments.
+
+def test(x, y):
+    div, mod = divmod(x, y)
+    print(div == x // y, mod == x % y, abs(div * y + mod - x) < 1e-6)
+
+test(1.23456, 0.7)
+test(-1.23456, 0.7)
+test(1.23456, -0.7)
+test(-1.23456, -0.7)
+
+a = 1.23456
+b = 0.7
+test(a, b)
+test(a, -b)
+test(-a, b)
+test(-a, -b)
+
+for i in range(25):
+    x = (i - 12.5) / 6
+    for j in range(25):
+        y = (j - 12.5) / 6
+        test(x, y)