Add tests for lib/rect

2 files changed, 258 insertions, 8 deletions

diff --git a/lib/rect.coffee b/lib/rect.coffee
index 67c9de7c..adc1fc36 100644
--- a/lib/rect.coffee
+++ b/lib/rect.coffee
@@ -9,8 +9,16 @@ Rect =
     width: x2 - x1
     height: y2 - y1
 
+  copy: (rect) ->
+    bottom: rect.bottom
+    top: rect.top
+    left: rect.left
+    right: rect.right
+    width: rect.width
+    height: rect.height
+
   # Translate a rect by x horizontally and y vertically.
-  translate: (rect, x, y) ->
+  translate: (rect, x = 0, y = 0) ->
     bottom: rect.bottom + y
     top: rect.top + y
     left: rect.left + x
@@ -19,18 +27,17 @@ Rect =
     height: rect.height
 
   # Subtract rect2 from rect1, returning an array of rects which are in rect1 but not rect2.
-  subtract: (rect1, rect2_) ->
+  subtract: (rect1, rect2) ->
     # Bound rect2 by rect1
-    rect2 = {}
     rect2 = @create(
-      Math.max(rect1.left, rect2_.left),
-      Math.max(rect1.top, rect2_.top),
-      Math.min(rect1.right, rect2_.right),
-      Math.min(rect1.bottom, rect2_.bottom)
+      Math.max(rect1.left, rect2.left),
+      Math.max(rect1.top, rect2.top),
+      Math.min(rect1.right, rect2.right),
+      Math.min(rect1.bottom, rect2.bottom)
     )
 
     # If bounding rect2 has made the width or height negative, rect1 does not contain rect2.
-    return [rect1] if rect2.width < 0 or rect2.height < 0
+    return [Rect.copy rect1] if rect2.width < 0 or rect2.height < 0
 
     #
     # All the possible rects, in the order
@@ -60,5 +67,16 @@ Rect =
 
     rects.filter (rect) -> rect.height > 0 and rect.width > 0
 
+  contains: (rect1, rect2) ->
+    rect1.right > rect2.left and
+    rect1.left < rect2.right and
+    rect1.bottom > rect2.top and
+    rect1.top < rect2.bottom
+
+  equals: (rect1, rect2) ->
+    for property in ["top", "bottom", "left", "right", "width", "height"]
+      return false if rect1[property] != rect2[property]
+    true
+
 root = exports ? window
 root.Rect = Rect
diff --git a/tests/unit_tests/rect_test.coffee b/tests/unit_tests/rect_test.coffee
new file mode 100644
index 00000000..cfb26b05
--- /dev/null
+++ b/tests/unit_tests/rect_test.coffee
@@ -0,0 +1,232 @@
+require "./test_helper.js"
+extend(global, require "../../lib/rect.js")
+
+context "Rect",
+  should "set rect properties correctly", ->
+    [x1, y1, x2, y2] = [1, 2, 3, 4]
+    rect = Rect.create x1, y1, x2, y2
+    assert.equal rect.left, x1
+    assert.equal rect.top, y1
+    assert.equal rect.right, x2
+    assert.equal rect.bottom, y2
+    assert.equal rect.width, x2 - x1
+    assert.equal rect.height, y2 - y1
+
+  should "translate rect horizontally", ->
+    [x1, y1, x2, y2] = [1, 2, 3, 4]
+    x = 5
+    rect1 = Rect.create x1, y1, x2, y2
+    rect2 = Rect.translate rect1, x
+
+    assert.equal rect1.left + x, rect2.left
+    assert.equal rect1.right + x, rect2.right
+
+    assert.equal rect1.width, rect2.width
+    assert.equal rect1.height, rect2.height
+    assert.equal rect1.top, rect2.top
+    assert.equal rect1.bottom, rect2.bottom
+
+  should "translate rect vertically", ->
+    [x1, y1, x2, y2] = [1, 2, 3, 4]
+    y = 5
+    rect1 = Rect.create x1, y1, x2, y2
+    rect2 = Rect.translate rect1, undefined, y
+
+    assert.equal rect1.top + y, rect2.top
+    assert.equal rect1.bottom + y, rect2.bottom
+
+    assert.equal rect1.width, rect2.width
+    assert.equal rect1.height, rect2.height
+    assert.equal rect1.left, rect2.left
+    assert.equal rect1.right, rect2.right
+
+context "Rect subtraction",
+  context "unchanged by rects outside",
+    should "left, above", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create -2, -2, -1, -1
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+    should "left", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create -2, 0, -1, 1
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+    should "left, below", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create -2, 2, -1, 3
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+    should "right, above", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create 2, -2, 3, -1
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+    should "right", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create 2, 0, 3, 1
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+    should "right, below", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create 2, 2, 3, 3
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+    should "above", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create 0, -2, 1, -1
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+    should "below", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create 0, 2, 1, 3
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+  context "unchanged by rects touching",
+    should "left, above", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create -1, -1, 0, 0
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+    should "left", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create -1, 0, 0, 1
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+    should "left, below", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create -1, 1, 0, 2
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+    should "right, above", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create 1, -1, 2, 0
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+    should "right", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create 1, 0, 2, 1
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+    should "right, below", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create 1, 1, 2, 2
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+    should "above", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create 0, -1, 1, 0
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+    should "below", ->
+      rect1 = Rect.create 0, 0, 1, 1
+      rect2 = Rect.create 0, 1, 1, 2
+
+      rects = Rect.subtract rect1, rect2
+      assert.equal rects.length, 1
+      rect = rects[0]
+      assert.isTrue Rect.equals rect1, rect
+
+  should "have nothing when subtracting itself", ->
+    rect = Rect.create 0, 0, 1, 1
+    rects = Rect.subtract rect, rect
+    assert.equal rects.length, 0
+
+  should "not overlap subtracted rect", ->
+    rect = Rect.create 0, 0, 3, 3
+    for x in [-2..2]
+      for y in [-2..2]
+        for width in [1..3]
+          for height in [1..3]
+            subtractRect = Rect.create x, y, (x + width), (y + height)
+            resultRects = Rect.subtract rect, subtractRect
+            for resultRect in resultRects
+              assert.isFalse Rect.contains subtractRect, resultRect
+
+  should "be contained in original rect", ->
+    rect = Rect.create 0, 0, 3, 3
+    for x in [-2..2]
+      for y in [-2..2]
+        for width in [1..3]
+          for height in [1..3]
+            subtractRect = Rect.create x, y, (x + width), (y + height)
+            resultRects = Rect.subtract rect, subtractRect
+            for resultRect in resultRects
+              assert.isTrue Rect.contains rect, resultRect
+
+  should "contain the  subtracted rect in the original minus the results", ->
+    rect = Rect.create 0, 0, 3, 3
+    for x in [-2..2]
+      for y in [-2..2]
+        for width in [1..3]
+          for height in [1..3]
+            subtractRect = Rect.create x, y, (x + width), (y + height)
+            resultRects = Rect.subtract rect, subtractRect
+            resultComplement = [Rect.copy rect]
+            for resultRect in resultRects
+              resultComplement = Array::concat.apply [],
+                (resultComplement.map (rect) -> Rect.subtract rect, resultRect)
+            assert.isTrue (resultComplement.length == 0 or resultComplement.length == 1)
+            if resultComplement.length == 1
+              complementRect = resultComplement[0]
+              assert.isTrue Rect.contains subtractRect, complementRect