jbrains · January 20, 2011 21:13 · Jan 20, 2011 · Jan 20, 2011
diff --git a/Cell.java b/Cell.java
@@ -0,0 +1,30 @@
+package rules;
+
+public class Cell {
+    protected int numberOfLiveNeighbors;
+    private CellState state;
+
+    public Cell() {
+        this.state = CellState.DEAD;
+    }
+
+    public Cell withLiveNeighbors(int numberOfLiveNeighbors) {
+        this.numberOfLiveNeighbors = numberOfLiveNeighbors;
+        return this;
+    }
+
+    public Cell thatIsAlive() {
+        this.state = CellState.ALIVE;
+        return this;
+    }
+
+    public boolean isAlive() {
+        return (state == CellState.ALIVE);
+    }
+
+    @Override
+    public String toString() {
+        return "I'm " + state + " and I have " + numberOfLiveNeighbors
+                + " live neighbors.";
+    }
+}
diff --git a/gistfile4.java → CellState.java b/gistfile4.java → CellState.java
diff --git a/EvolveCellOneGeneration.groovy b/EvolveCellOneGeneration.groovy
@@ -0,0 +1,29 @@
+package rules
+
+import spock.lang.Specification
+import spock.lang.Unroll
+
+class EvolveCellOneGeneration extends Specification {
+    @Unroll("a dead cell with #liveNeighbors live neighbors dies")
+    def "rules for cells to live or die"() {
+        given:
+        def inNextGeneration = new RulesForNextGeneration()
+        def cell = initiallyAlive ? new Cell().thatIsAlive().withLiveNeighbors(liveNeighbors) : new Cell().withLiveNeighbors(liveNeighbors)
+
+        expect:
+        inNextGeneration.itTurnsOutThat(cell).comesAlive() == endsUpAlive
+
+        where:
+        liveNeighbors | initiallyAlive | endsUpAlive
+        0 | false | false
+        1 | false | false
+        2 | false | false
+        3 | false | true
+        4 | false | false
+        0 | true | false
+        1 | true | false
+        2 | true | true
+        3 | true | true
+        4 | true | false
+    }
+}
diff --git a/gistfile2.java → RulesForNextGeneration.java b/gistfile2.java → RulesForNextGeneration.java
diff --git a/RulesForNextGenerationTest → RulesForNextGenerationTest.java b/RulesForNextGenerationTest → RulesForNextGenerationTest.java
diff --git a/gistfile3.java b/gistfile3.java
@@ -1,25 +0,0 @@
-package rules;
-
-public class Cell {
-  protected int numberOfLiveNeighbors;
-  private CellState state;
-
-  public Cell() {
-    this.state = CellState.DEAD;
-  }
-
-  public Cell withLiveNeighbors(int numberOfLiveNeighbors) {
-    this.numberOfLiveNeighbors = numberOfLiveNeighbors;
-    return this;
-  }
-
-  public Cell thatIsAlive() {
-    this.state = CellState.ALIVE;
-    return this;
-  }
-
-  public boolean isAlive() {
-    return (state == CellState.ALIVE);
-  }
-
-}

diff --git a/RulesForNextGenerationTest b/RulesForNextGenerationTest
@@ -0,0 +1,88 @@
+package rules;
+
+import static org.junit.Assert.*;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class RulesForNextGenerationTest {
+  private RulesForNextGeneration inNextGeneration;
+
+  @Before
+  public void setup() {
+    inNextGeneration = new RulesForNextGeneration();
+  }
+
+  @Test
+  public void deadCellWith_0_LiveNeighbors_StaysDead() throws Exception {
+    assertIsDeadNextTime(new Cell().withLiveNeighbors(0));
+  }
+
+  @Test
+  public void deadCellWith_1_LiveNeighbors_StaysDead() throws Exception {
+    assertIsDeadNextTime(new Cell().withLiveNeighbors(1));
+  }
+
+  @Test
+  public void deadCellWith_2_LiveNeighbors_StaysDead() throws Exception {
+    assertIsDeadNextTime(new Cell().withLiveNeighbors(2));
+  }
+
+  @Test
+  public void deadCellWith_3_LiveNeighbors_ComesAlive() throws Exception {
+    assertIsAliveNextTime(new Cell().withLiveNeighbors(3));
+  }
+
+  @Test
+  public void deadCellWith_4_LiveNeighbors_staysdead() throws Exception {
+    assertIsDeadNextTime(new Cell().withLiveNeighbors(4));
+  }
+
+  @Test
+  public void liveCellWith_0_LiveNeighbors_Dies() throws Exception {
+    assertIsDeadNextTime(new Cell().thatIsAlive().withLiveNeighbors(0));
+  }
+
+  @Test
+  public void liveCellWith_1_LiveNeighbors_Dies() throws Exception {
+    assertIsDeadNextTime(new Cell().thatIsAlive().withLiveNeighbors(1));
+  }
+
+  @Test
+  public void liveCellWith_2_LiveNeighbors_StaysAlive() throws Exception {
+    assertIsAliveNextTime(new Cell().thatIsAlive().withLiveNeighbors(2));
+  }
+
+  @Test
+  public void liveCellWith_3_LiveNeighbors_StaysAlive() throws Exception {
+    assertIsAliveNextTime(new Cell().thatIsAlive().withLiveNeighbors(3));
+  }
+
+  @Test
+  public void liveCellWith_4_LiveNeighbors_Dies() throws Exception {
+    assertIsDeadNextTime(new Cell().thatIsAlive().withLiveNeighbors(4));
+  }
+
+  private void assertIsAliveNextTime(Cell cell) {
+    assertTrue(inNextGeneration.itTurnsOutThat(cell).comesAlive());
+  }
+
+  private void assertIsDeadNextTime(Cell cell) {
+    assertFalse(inNextGeneration.itTurnsOutThat(cell).comesAlive());
+  }
+
+  // Test list
+
+  // TODO a dead cell with 0 live neighbors stays dead.
+  // TODO a dead cell with 1 live neighbors stays dead.
+  // TODO a dead cell with 2 live neighbors stays dead.
+  // TODO a dead cell with 3 live neighbors comes alive.
+  // TODO a dead cell with 4 live neighbors stays dead.
+
+  // TODO a live cell with 0 live neighbors dies.
+  // TODO a live cell with 1 live neighbor dies.
+  // TODO a live cell with 2 live neighbors stays alive.
+  // TODO a live cell with 3 live neighbors stays alive.
+  // TODO a live cell with 4 live neighbors dies.
+
+}
diff --git a/gistfile2.java b/gistfile2.java
@@ -0,0 +1,15 @@
+package rules;
+
+public class RulesForNextGeneration {
+  private Cell cell;
+
+  public RulesForNextGeneration itTurnsOutThat(Cell cell) {
+    this.cell = cell;
+    return this;
+  }
+
+  public boolean comesAlive() {
+    if (cell.isAlive() && cell.numberOfLiveNeighbors == 2) return true;
+    return (cell.numberOfLiveNeighbors == 3);
+  }
+}
diff --git a/gistfile3.java b/gistfile3.java
@@ -0,0 +1,25 @@
+package rules;
+
+public class Cell {
+  protected int numberOfLiveNeighbors;
+  private CellState state;
+
+  public Cell() {
+    this.state = CellState.DEAD;
+  }
+
+  public Cell withLiveNeighbors(int numberOfLiveNeighbors) {
+    this.numberOfLiveNeighbors = numberOfLiveNeighbors;
+    return this;
+  }
+
+  public Cell thatIsAlive() {
+    this.state = CellState.ALIVE;
+    return this;
+  }
+
+  public boolean isAlive() {
+    return (state == CellState.ALIVE);
+  }
+
+}
diff --git a/gistfile4.java b/gistfile4.java
@@ -0,0 +1,5 @@
+package rules;
+
+public enum CellState {
+  DEAD, ALIVE
+}