Fix large grid displays

game-of-life/src/main/java/fr/ippon/life/Grid.java

@@ -8,21 +8,26 @@ import java.util.stream.Stream;
 
 public class Grid {
 
+  private final Set<Cell> aliveCells;
   private final Set<Cell> deadCells;
   private final Box border;
 
   Grid(Set<Cell> aliveCells) {
+    this.aliveCells = aliveCells;
     this.deadCells = buildDeadCells(aliveCells);
     border = new Box(aliveCells);
   }
 
   private Set<Cell> buildDeadCells(Set<Cell> aliveCells) {
-    return aliveCells
-      .stream()
-      .map(Box::new)
-      .flatMap(Box::cells)
-      .filter(cell -> !aliveCells.contains(cell))
-      .collect(Collectors.toUnmodifiableSet());
+    return aliveCells.stream()
+        .map(Box::new)
+        .flatMap(Box::cells)
+        .filter(cell -> !aliveCells.contains(cell))
+        .collect(Collectors.toUnmodifiableSet());
+  }
+
+  public boolean isAlive(Cell cell) {
+    return aliveCells.contains(cell);
   }
 
   public Collection<Cell> deadCells() {
@@ -60,11 +65,15 @@ public class Grid {
     }
 
     private Stream<Cell> cells() {
-      return IntStream.range(leftColumn(), rightColumn()).mapToObj(Integer::valueOf).flatMap(column -> cellsColumn(column));
+      return IntStream.range(leftColumn(), rightColumn())
+          .mapToObj(Integer::valueOf)
+          .flatMap(column -> cellsColumn(column));
     }
 
     private Stream<Cell> cellsColumn(Integer column) {
-      return IntStream.range(topRow(), bottomRow()).mapToObj(Integer::valueOf).map(row -> new Cell(row, column));
+      return IntStream.range(topRow(), bottomRow())
+          .mapToObj(Integer::valueOf)
+          .map(row -> new Cell(row, column));
     }
 
     public int topRow() {
@@ -95,17 +104,29 @@ public class Grid {
     }
 
     private static Point topLeft(Set<Cell> cells) {
-      int row = cells.stream().mapToInt(Cell::row).min().orElse(0);
+      int row = cells.stream()
+          .mapToInt(Cell::row)
+          .min()
+          .orElse(0);
 
-      int column = cells.stream().mapToInt(Cell::column).min().orElse(0);
+      int column = cells.stream()
+          .mapToInt(Cell::column)
+          .min()
+          .orElse(0);
 
       return new Point(row - 1, column - 1);
     }
 
     private static Point bottomRight(Set<Cell> cells) {
-      int row = cells.stream().mapToInt(Cell::row).max().orElse(0);
-
-      int column = cells.stream().mapToInt(Cell::column).max().orElse(0);
+      int row = cells.stream()
+          .mapToInt(Cell::row)
+          .max()
+          .orElse(0);
+
+      int column = cells.stream()
+          .mapToInt(Cell::column)
+          .max()
+          .orElse(0);
 
       return new Point(row + 1, column + 1);
     }

game-of-life/src/main/java/fr/ippon/life/StringRenderer.java

@@ -21,28 +21,31 @@ public class StringRenderer implements Renderer<String> {
 
     private String run() {
       return IntStream
-        .range(grid.topRow(), grid.bottomRow())
-        .mapToObj(Integer::valueOf)
-        .map(row -> rowRepresentation(grid, row))
-        .collect(Collectors.joining(System.lineSeparator(), "", System.lineSeparator()));
+          .range(grid.topRow(), grid.bottomRow())
+          .mapToObj(Integer::valueOf)
+          .map(row -> rowRepresentation(grid, row))
+          .collect(
+              Collectors.joining(System.lineSeparator(), "",
+                  System.lineSeparator()));
     }
 
-    private String rowRepresentation(Grid grid, Integer row) {
-      return IntStream.range(grid.leftColumn(), grid.rightColumn()).mapToObj(cellRepresentation(row)).collect(Collectors.joining());
+    private String rowRepresentation(Grid grid,
+        Integer row) {
+      return IntStream
+          .range(grid.leftColumn(), grid.rightColumn())
+          .mapToObj(cellRepresentation(row))
+          .collect(Collectors.joining());
     }
 
-    private IntFunction<String> cellRepresentation(Integer row) {
+    private IntFunction<String> cellRepresentation(
+        Integer row) {
       return column -> {
-        if (aliveCell(row, column)) {
+        if (grid.isAlive(new Cell(row, column))) {
           return "o";
         }
 
         return "x";
       };
     }
-
-    private boolean aliveCell(Integer row, int column) {
-      return !grid.deadCells().contains(new Cell(row, column));
-    }
   }
 }

game-of-life/src/test/java/fr/ippon/life/StringRendererUnitTest.java

@@ -14,16 +14,30 @@ class StringRendererUnitTest {
 
   @Test
   void shouldDisplayGridWithOneAliveCell() {
-    assertThat(renderer.run(grid().alive(1, 1).build())).isEqualTo(join("xxx", "xox", "xxx"));
+    assertThat(renderer.run(grid().alive(1, 1)
+        .build())).isEqualTo(join("xxx", "xox", "xxx"));
   }
 
   @Test
   void shouldDisplayGridWithTwoAliveCell() {
-    assertThat(renderer.run(grid().alive(1, 1).alive(1, 3).build())).isEqualTo(join("xxxxx", "xoxox", "xxxxx"));
+    assertThat(renderer.run(grid().alive(1, 1)
+        .alive(1, 3)
+        .build()))
+            .isEqualTo(join("xxxxx", "xoxox", "xxxxx"));
+  }
+
+  @Test
+  void shouldDisplayGridWithTwoDistantAliveCell() {
+    assertThat(renderer.run(grid().alive(1, 1)
+        .alive(1, 7)
+        .build())).isEqualTo(
+            join("xxxxxxxxx", "xoxxxxxox", "xxxxxxxxx"));
   }
 
   private static String join(String... parts) {
-    return Arrays.stream(parts).collect(Collectors.joining(System.lineSeparator(), "", System.lineSeparator()));
+    return Arrays.stream(parts)
+        .collect(Collectors.joining(System.lineSeparator(),
+            "", System.lineSeparator()));
   }
 
   private GridBuilder grid() {