experiments/cellular-automata
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Add .get method for coordinate element retrieval to grid

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Coordinates passed in access the correct index in the internal list.
This commit is contained in:
Marty Oehme 2018-08-30 09:43:46 +02:00
parent 46b11bc33b
commit 6c3fcbe7b0
2 changed files with 24 additions and 5 deletions
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8
lib/src/Grid.dart
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@ -21,10 +21,10 @@ class Grid<E> extends DelegatingList<E> {
height = h,
super(l);
E elementAtPos(int x, int y) {
E get(int x, int y) {
int i = toIndex(x, y);
if (i >= length) throw RangeError.index(i, this);
_internal[i];
if (i >= length || x > width - 1) throw RangeError.index(i, this);
return _internal[i];
}
void setElement(int x, int y, E value) {
@ -33,8 +33,6 @@ class Grid<E> extends DelegatingList<E> {
_internal[i] = value;
}
E get(int x, int y) => elementAtPos(x, y);
void set(int x, int y, E value) => setElement(x, y, value);
/// Calculate list index from coordinates.

21
test/src/grid_test.dart
View file

@ -92,6 +92,27 @@ void main() {
expect(sut.toIndex(1, 1), equals(4));
}, tags: const ["happy"]);
});
group("coordinates getter", () {
Grid sut;
setUp(() {
sut = Grid(3, 3);
sut.setAll(0,
["Hey", "you", "me", "together", "Hello", null, "I", "am", "ready."]);
});
test("returns null if no element exists at the position requested", () {
expect(sut.get(2, 1), null);
}, tags: const ["sad"]);
test("throws RangeError if requesting element outside of grid width", () {
expect(() => sut.get(4, 1), throwsRangeError);
}, tags: const ["bad"]);
test("throws RangeError if requesting element outside of grid height", () {
expect(() => sut.get(1, 4), throwsRangeError);
}, tags: const ["bad"]);
test("returns element at correct index", () {
expect(sut.get(1, 0), "you");
}, tags: const ["happy"]);
test("returns last element correctly", () {
expect(sut.get(2, 2), "ready.");
}, tags: const ["happy"]);
});
}