add tests for edge cases

src/exponent.c

@@ -24,21 +24,27 @@ double expI(double e, double num){
 
 double expIN(double e, double num){
     if(absD(e) - ((int) absD(e)) < 0.000001){
-        if(e>0.0){
+        if(e>=0.0){
             return expI(e, num);
         }
         else{
+            if (num == 0.0){
+                return -1.0;
+            }
             return  (1.0 / expI((e*-1), num));
         }   
     }else if(num > 0.0){
-        if(e>0.0){
+        if(e>=0.0){
             return exponential(e*logN(num, 0.00000001));
         }
         else{
+            if (num == 0.0){
+                return -1.0;
+            }
             return (1.0 / exponential((-1*e)*logN(num, 0.00000001)));
         }
     }
-    return -1;
+    return -1.0;
 }
 
 unsigned long long fac(int x){

test/test_exponent.c

@@ -84,6 +84,22 @@ void test_DoubleDecimalBase_for_negative_decimal_exponent(void){
     TEST_ASSERT_DOUBLE_WITHIN(0.0001, 0.000964, r3);
 }
 
+void test_exponent_edge_case(void){
+    float r1, r2, r3, r4, r5;
+
+    r1 = expIN(0, 2);
+    r2 = expIN(0, 0);
+    r3 = expIN(2, 0);
+    r4 = expIN(-3, 0);
+    r5 = expIN(0.5, -3);
+
+    TEST_ASSERT_DOUBLE_WITHIN(0.0001, 1.0, r1);
+    TEST_ASSERT_DOUBLE_WITHIN(0.0001, 1.0, r2);
+    TEST_ASSERT_DOUBLE_WITHIN(0.0001, 0.0, r3);
+    TEST_ASSERT_DOUBLE_WITHIN(0.0001, -1.0, r4);
+    TEST_ASSERT_DOUBLE_WITHIN(0.0001, -1.0, r5);
+}
+
 void test_Exponent_with_positive_number(void){
     double r1, r2, r3;