refactor to string input for validatoin

src/main/java/io/tripled/marsrover/commands/CreateGrid.kt

@@ -4,9 +4,9 @@ import io.tripled.marsrover.Grids
 import io.tripled.marsrover.domain.Grid
 
 class CreateGrid(private val grids: Grids) {
-    fun create(gridSize: Int) {
+    fun create(gridSize: String) {
 
-        grids.save(Grid(gridSize))
+        grids.save(Grid(gridSize.toInt()))
     }
 
 }

src/test/java/io/tripled/marsrover/GridTests.kt

@@ -3,13 +3,14 @@ package io.tripled.marsrover
 import io.tripled.marsrover.commands.CreateGrid
 import io.tripled.marsrover.domain.Grid
 import org.junit.jupiter.api.Assertions
+import org.junit.jupiter.api.Disabled
 import org.junit.jupiter.api.Test
 
 internal class GridTests {
     @Test
     fun `creates a grid`() {
         // given
-        val gridSize = 6
+        val gridSize = "6"
         val grids = FakeGrids()
 
         // when
@@ -18,6 +19,20 @@ internal class GridTests {
         // then
         Assertions.assertEquals(grids.lastSaved.numberOfCoordinates, 36)
     }
+
+    @Disabled
+    @Test
+    fun `input validation`() {
+        // given
+        val requestedGridSize = "6"
+        val grids = FakeGrids()
+
+        // when
+        CreateGrid(grids).create(requestedGridSize)
+
+        // then
+        Assertions.assertEquals(grids.lastSaved.numberOfCoordinates, 36)
+    }
 }
 
 class FakeGrids : Grids {