Add implementations for isProperFraction including boundary and invalid case tests

Author: ChinweP

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

@@ -12,6 +12,10 @@
 
 function isProperFraction(numerator, denominator) {
   // TODO: Implement this function
+ if (denominator === 0) {
+    return false;
+  }
+  return numerator < denominator;
 }
 
 // The line below allows us to load the isProperFraction function into tests in other files.
@@ -31,3 +35,24 @@ function assertEquals(actualOutput, targetOutput) {
 
 // Example: 1/2 is a proper fraction
 assertEquals(isProperFraction(1, 2), true);
+// Proper fractions
+assertEquals(isProperFraction(2, 3), true);
+assertEquals(isProperFraction(3, 4), true);
+assertEquals(isProperFraction(0, 5), true);
+
+// Improper fractions
+assertEquals(isProperFraction(5, 5), false);
+assertEquals(isProperFraction(7, 3), false);
+
+// Denominator zero
+assertEquals(isProperFraction(5, 0), false);
+
+// Negative numerators
+assertEquals(isProperFraction(-1, 2), true);
+
+// Negative denominators
+assertEquals(isProperFraction(1, -2), false);
+
+// Both negative
+assertEquals(isProperFraction(-3, -2), false);
+