diff --git a/.gitignore b/.gitignore
index 5e56e040..81631c69 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 /bin
+/build
diff --git a/tests/execute.py b/tests/execute.py
index 5c1e9744..48e33169 100644
--- a/tests/execute.py
+++ b/tests/execute.py
@@ -5,6 +5,7 @@
 import os
 import re
 import subprocess
+from math import isclose
 
 
 floatPattern = re.compile("""(
@@ -45,8 +46,9 @@ def lineEquivalence(ref, trial, n, relativeError=1E-9, absoluteError=1E-10):
             else:
                 # Look at all the floats on the lines
                 for rF, tF in zip(refFloats, trialFloats):
-                    equal = fuzzyDiff(makeFloat(rF), makeFloat(tF),
-                                      relativeError, absoluteError)
+                    equal = isclose( makeFloat(rF), makeFloat(tF),
+                                     rel_tol = relativeError,
+                                     abs_tol = absoluteError )
                     if not equal:
                         print("{} and {} are not equal".format(
                             rF[0], tF[0]))
@@ -82,6 +84,7 @@ def identicalLines(refLines, trialLines, diffFile,
     for n, (ref, trial) in enumerate(zip(refLines, trialLines)):
         equivalent = lineEquivalence(ref, trial, n,
                                      relativeError, absoluteError)
+
         if not equivalent:
             fullEquivalence = False
             writeDiff(diffFile, ref, trial, n)
@@ -112,15 +115,6 @@ def writeDiff(diff_file, refLine, trialLine, lineNumber):
     diff_file.write("!{}".format(trialLine))
 
 
-def fuzzyDiff(a, b, relativeError=1E-9, absoluteError=1E-10):
-    """
-    fuzzDiff will compare to numbers (a and b) to see if they are identical
-    within the given tolerance. Returns bool.
-    """
-    delta = max(abs(a), abs(b))*relativeError + absoluteError
-    return (abs(a - b) <= abs(delta))
-
-
 retained_tapes = set(glob.glob('tape*'))
 reference_tapes = glob.glob('referenceTape*')
 
@@ -152,7 +146,7 @@ def fuzzyDiff(a, b, relativeError=1E-9, absoluteError=1E-10):
                 diff_file.write("--- {} ---\n".format(trial_tape))
 
                 identical = identicalLines(
-                    reference_lines, trial_lines, diff_file, 1E-7, 1E-7)
+                    reference_lines, trial_lines, diff_file, 1E-9, 1e-10)
                 should_exit = not identical
 
             if should_exit: