Add i ProperFraction function with tests

Author: Pretty Taruvinga

Sprint-3/1-implement-and-rewrite-tests/implement/2-is-proper-fraction.js

@@ -11,9 +11,10 @@
 // execute the code to ensure all tests pass.
 
 function isProperFraction(numerator, denominator) {
-  // TODO: Implement this function
+  if (denominator === 0) return false;
+  return Math.abs(numerator) < Math.abs(denominator);
 }
-
+//
 // The line below allows us to load the isProperFraction function into tests in other files.
 // This will be useful in the "rewrite tests with jest" step.
 module.exports = isProperFraction;
@@ -31,3 +32,9 @@ function assertEquals(actualOutput, targetOutput) {
 
 // Example: 1/2 is a proper fraction
 assertEquals(isProperFraction(1, 2), true);
+assertEquals(isProperFraction(2, 1), false);
+assertEquals(isProperFraction(-1, 2), true);
+assertEquals(isProperFraction(1, -2), true);
+assertEquals(isProperFraction(-1, -2), true);
+assertEquals(isProperFraction(0, 2), true);
+assertEquals(isProperFraction(2, 0), false);