Added getMonthValueByString function to DayCalculator, with tests

lib/DayCalculator.dart

@@ -50,6 +50,47 @@ class DayCalculator {
     }
   }
 
+  static int getMonthValueByString(String month){
+    switch(month){
+      case "January":{
+        return 0;
+      }
+      case "February":{
+        return 3;
+      }
+      case "March":{
+        return 3;
+      }
+      case "April":{
+        return 6;
+      }
+      case "May":{
+        return 1;
+      }
+      case "June":{
+        return 4;
+      }
+      case "July":{
+        return 6;
+      }
+      case "August":{
+        return 2;
+      }
+      case "September":{
+        return 5;
+      }
+      case "October":{
+        return 0;
+      }
+      case "November":{
+        return 3;
+      }
+      default:{
+        return 5;
+      }
+    }
+  }
+
   static int getCenturyValue(int year){
     // Returns the century code for the year
     // TODO: Implement Julian calendar?

test/widget_test.dart

@@ -54,6 +54,44 @@ void main() {
       expect(DayCalculator.getMonthValue(11), equals(5));
     });
   });
+  group("DayCalculator getMonthValueByString()", () {
+    test("January", () {
+      expect(DayCalculator.getMonthValueByString("January"), equals(0));
+    });
+    test("February", () {
+      expect(DayCalculator.getMonthValueByString("February"), equals(3));
+    });
+    test("March", () {
+      expect(DayCalculator.getMonthValueByString("March"), equals(3));
+    });
+    test("April", () {
+      expect(DayCalculator.getMonthValueByString("April"), equals(6));
+    });
+    test("May", () {
+      expect(DayCalculator.getMonthValueByString("May"), equals(1));
+    });
+    test("June", () {
+      expect(DayCalculator.getMonthValueByString("June"), equals(4));
+    });
+    test("July", () {
+      expect(DayCalculator.getMonthValueByString("July"), equals(6));
+    });
+    test("August", () {
+      expect(DayCalculator.getMonthValueByString("August"), equals(2));
+    });
+    test("September", () {
+      expect(DayCalculator.getMonthValueByString("September"), equals(5));
+    });
+    test("October", () {
+      expect(DayCalculator.getMonthValueByString("October"), equals(0));
+    });
+    test("November", () {
+      expect(DayCalculator.getMonthValueByString("November"), equals(3));
+    });
+    test("December", () {
+      expect(DayCalculator.getMonthValueByString("December"), equals(5));
+    });
+  });
   group("DayCalculator getCenturyValue()", () {
     group("1700s", () {
       test("1700", (){