Add simple Grid - List Wrapper Data Structure

lib/src/Grid.dart

@@ -0,0 +1,22 @@
+import 'dart:core';
+
+import 'package:collection/collection.dart';
+
+class Grid<E> extends DelegatingList<E> {
+  final List<E> _internal;
+  final width;
+  final height;
+
+  Grid(int width, int height) : this._(List<E>(width * height), width, height);
+
+  Grid.from(Grid<E> l)
+      : this._(List<E>.from(l.getRange(0, l.length)), l.width, l.height);
+
+  Grid.fromList(List<E> l, int width) : this._(l, width, l.length ~/ width);
+
+  Grid._(l, int w, int h)
+      : _internal = l,
+        width = w,
+        height = h,
+        super(l);
+}

test/src/grid_test.dart

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+import 'package:rules_of_living/src/Grid.dart';
+import 'package:test/test.dart';
+
+@Tags(const ["nobrowser"])
+void main() {
+  Grid sut;
+  group("Instantiation", () {
+    List<String> l;
+    setUp(() {
+      l = [
+        "Hey",
+        "you",
+        "me",
+        "together",
+        "Hello",
+        "World",
+        "I",
+        "am",
+        "ready."
+      ];
+    });
+    test("gets created with the correct length for given quadratic gridsize",
+        () {
+      Grid sut = Grid(3, 3);
+      expect(sut.length, 9);
+    });
+    test("gets created with the correct length for given rectangular gridsize",
+        () {
+      Grid sut = Grid(87, 85);
+      expect(sut.length, 7395);
+    });
+    test("copies the content of another grid on .from Constructor call", () {
+      Grid original = Grid(2, 2);
+      original[0] = "Hey";
+      original[1] = "you";
+      original[2] = "me";
+      original[3] = "together";
+
+      Grid sut = Grid.from(original);
+      expect(sut, containsAllInOrder(["Hey", "you", "me", "together"]));
+    });
+    test("copies the length of another grid on .from Constructor call", () {
+      Grid original = Grid(2, 2);
+      original[0] = "Hey";
+      original[1] = "you";
+      original[2] = "me";
+      original[3] = "together";
+
+      Grid sut = Grid.from(original);
+      expect(sut.length, 4);
+    });
+    test("sets the length for list passed in on .fromList Constructor call",
+        () {
+      Grid sut = Grid.fromList(l, 3);
+
+      expect(sut.length, 9);
+    });
+    test("sets the contents of list passed in on .fromList Constructor call",
+        () {
+      Grid sut = Grid.fromList(l, 3);
+
+      expect(sut[3], "together");
+    });
+    test(
+        "sets the correct height for list passed in on .fromList Constructor call",
+        () {
+      Grid sut = Grid.fromList(l, 3);
+
+      expect(sut.width, 3);
+    });
+  });
+  group("getter", () {
+    setUp(() {
+      sut = Grid(3, 3);
+      sut.setAll(0, [
+        "Hey",
+        "you",
+        "me",
+        "together",
+        "Hello",
+        "World",
+        "I",
+        "am",
+        "ready."
+      ]);
+    });
+    test("Engine can be instantiated without canvas", () {
+      expect(sut, isNot(throwsNoSuchMethodError));
+    });
+  });
+}