Apply filter to float_with_bounds

Computing floats when given bounds such as min -9.9e15 and max -1 will result in
the computation `-1.0 - -9.9e15` yielding 9900000000000000.0 instead of
9899999999999999.0, which makes the generator return 0. This is a classic
floating point loss of significance error.

Fixes #203

Author: Munksgaard

lib/stream_data.ex

@@ -1756,6 +1756,9 @@ defmodule StreamData do
       bind(exponent_data, fn exponent ->
         map(float_in_0_to_1(exponent), fn float -> float * (max - min) + min end)
       end)
+      |> filter(fn float ->
+        min <= float and float <= max
+      end)
     end)
   end
 

test/stream_data_test.exs

@@ -330,6 +330,14 @@ defmodule StreamDataTest do
         assert float >= -1.12 and float <= 4.01
       end
     end
+
+    property "with a large negative :min and :max option" do
+      # The large negative min might cause loss of significance.
+      check all float <- float(min: -9.9e25, max: -1) do
+        assert is_float(float)
+        assert float <= -1
+      end
+    end
   end
 
   property "byte/0" do