[Hacker Rank]: Project Euler #3: Largest prime factor. Coverage increased.

Author: Gonzalo Diaz

algorithm-exercises-java/src/main/java/ae/hackerrank/projecteuler/Euler003.java

@@ -11,7 +11,7 @@ private Euler003() {}
 
   private static Long primeFactor(Long n) {
     if (n < 2) {
-      return null;
+      throw new IllegalArgumentException("n must be greater than 2");
     }
 
     Long divisor = n;

algorithm-exercises-java/src/test/java/ae/hackerrank/projecteuler/Euler003Test.java

@@ -1,13 +1,17 @@
 package ae.hackerrank.projecteuler;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.IOException;
 import java.util.List;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.TestInstance;
 import org.junit.jupiter.api.TestInstance.Lifecycle;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 import util.JsonLoader;
 
 
@@ -45,4 +49,22 @@ public void setup() throws IOException {
       );
     }
   }
+
+  @ParameterizedTest
+  @CsvSource({
+      "0",
+      "1"
+  }) void euler003edgecases(long input) {
+
+    Exception exception;
+
+    exception = assertThrows(IllegalArgumentException.class, () ->
+        Euler003.euler003(input)
+    );
+
+    String expectedMessage = "n must be greater than 2";
+
+    assertTrue(exception.getMessage().contains(expectedMessage));
+
+  }
 }