diff --git a/src/RomanNumerals.java b/src/RomanNumerals.java
index 20904f0..5ce946b 100644
--- a/src/RomanNumerals.java
+++ b/src/RomanNumerals.java
@@ -1,8 +1,55 @@
+import java.util.LinkedHashMap;
 
 public class RomanNumerals {
-	public int convertToInteger(String romanNum) {
-		// To be Implemented
-		return 0;
+	public int convertToInteger(String romanNum) throws Exception {
 		
+		String[] num = romanNum.toUpperCase().split("");
+		int sum = 0;
+		
+		if(!checkLegal(romanNum))
+			throw new Exception("Illegal numeral");
+		
+		LinkedHashMap<String, Integer> map = new LinkedHashMap<String, Integer>();
+		map.put("M", 1000);
+	//	map.put("CM", 900);
+		map.put("D", 500);
+	//	map.put("CD", 400);
+		map.put("C", 100);
+	//	map.put("XC", 90);
+		map.put("L", 50);
+	//	map.put("XL", 40);
+		map.put("X", 10);
+	//	map.put("IX", 9);
+		map.put("V", 5);
+	//	map.put("IV", 4);
+		map.put("I", 1);
+		
+		for (int i=0; i<num.length - 1; i++) {
+			if (map.get(num[i]) < map.get(num[i+1])) 
+				sum -= map.get(num[i]);
+			else
+				sum += map.get(num[i]); 
+				
+		}
+		sum += map.get(num[(num.length -1)]) ;
+		return sum;
+		
+		
+		
+	}
+	
+	//Check for non Roman numeral and repetition
+	public boolean checkLegal(String romanNum) {
+		if (romanNum == "")
+			return false;
+		if (!romanNum.matches("[IVXLCDM]+"))
+			return false;
+		if (romanNum.contains("IIII") || romanNum.contains("CCCC") || romanNum.contains("XXXX") || romanNum.contains("MMMM"))
+			return false;
+		if (romanNum.contains("VV") || romanNum.contains("LL") || romanNum.contains("DD"))
+			return false;	
+		if (romanNum.contains("VD") || romanNum.contains("VL") || romanNum.contains("LD"))
+			return false;	
+		return true;
 	}
 }
diff --git a/tests/TestRomanNumerals.java b/tests/TestRomanNumerals.java
index 5d1de75..450ca61 100644
--- a/tests/TestRomanNumerals.java
+++ b/tests/TestRomanNumerals.java
@@ -4,9 +4,71 @@
 
 public class TestRomanNumerals {
 
+	@Test (expected = Exception.class)
+	public void testIllegalRepeatTriple() throws Exception {
+		RomanNumerals num = new RomanNumerals();
+		num.convertToInteger("DMCCCCV");
+	}
+	
+	@Test (expected = Exception.class)
+	public void testIllegalRepeatDouble() throws Exception {
+		RomanNumerals num = new RomanNumerals();
+		num.convertToInteger("DMCCVV");
+	}
+	
+	@Test (expected = Exception.class)
+	public void testIllegalSymbol() throws Exception {
+		RomanNumerals num = new RomanNumerals();
+		num.convertToInteger("B");
+	}
+	
+	@Test
+	public void testSingles() throws Exception {
+		RomanNumerals num = new RomanNumerals();
+		assertEquals(1,num.convertToInteger("I"));
+		assertEquals(5,num.convertToInteger("V"));
+		assertEquals(10,num.convertToInteger("X"));
+		assertEquals(50,num.convertToInteger("L"));
+		assertEquals(100,num.convertToInteger("C"));
+		assertEquals(500,num.convertToInteger("D"));
+		assertEquals(1000,num.convertToInteger("M"));
+	}
+	
 	@Test
-	public void test() {
-		fail("Not yet implemented");
+	public void testDoubles() throws Exception {
+		RomanNumerals num = new RomanNumerals();
+		assertEquals(2,num.convertToInteger("II"));
+		assertEquals(20,num.convertToInteger("XX"));
+		assertEquals(200,num.convertToInteger("CC"));
+		assertEquals(2000,num.convertToInteger("MM"));
+	}
+	
+	@Test
+	public void testAddition() throws Exception {
+		RomanNumerals num = new RomanNumerals();
+		assertEquals(11,num.convertToInteger("XI"));
+		assertEquals(15,num.convertToInteger("XV"));
+		assertEquals(32,num.convertToInteger("XXXII"));
+		assertEquals(102,num.convertToInteger("CII"));
+		assertEquals(2016,num.convertToInteger("MMXVI"));
+	}
+	
+	@Test
+	public void testSubstraction() throws Exception {
+		RomanNumerals num = new RomanNumerals();
+		assertEquals(4,num.convertToInteger("IV"));
+		assertEquals(9,num.convertToInteger("IX"));
+		assertEquals(14,num.convertToInteger("XIV"));
+		assertEquals(19,num.convertToInteger("XIX"));
+		assertEquals(49,num.convertToInteger("XLIX"));
+		assertEquals(2453,num.convertToInteger("MMCDLIII"));
+	}
+	
+	@Test (expected = Exception.class)
+	public void testIllegalSubstraction() throws Exception {
+		RomanNumerals num = new RomanNumerals();
+		num.convertToInteger("VL");
+		num.convertToInteger("VD");
 	}
 
 }