Merge pull request #57 from open-craft/jill/feature-item-alignment

Allow to set automatic alignment of dragged items in drop zones (second attempt)

Changelog.md

+Development version:
+--------------------
+
+* Added the ability to specify automatic alignment of dropped items. (PR #57)
+
 Version 2.0.4 (2016-03-10)
 --------------------------
 

README.md

@@ -11,6 +11,7 @@ The editor is fully guided. Features include:
 * custom zone labels
 * ability to show or hide zone borders
 * custom text and background colors for items
+* optional auto-alignment for items (left, right, center)
 * image items
 * items prompting for additional (numerical) input after being dropped
 * decoy items that don't have a zone
@@ -102,7 +103,7 @@ above the background image, the introductory feedback (shown
 initially), and the final feedback (shown after the learner
 successfully completes the drag and drop problem).
 
-![Drop zone edit](https://raw.githubusercontent.com/edx-solutions/xblock-drag-and-drop-v2/c955a38dc3a1aaf609c586d293ce19b282e11ffd/doc/img/edit-view-zones.png)
+![Drop zone edit](https://raw.githubusercontent.com/edx-solutions/xblock-drag-and-drop-v2/ebd0b52d971bbf93b9c3873f310bd72d336d865b/doc/img/edit-view-zones.png)
 
 In the next step, you set the URL and description for the background
 image and define the properties of the drop zones. For each zone you
@@ -114,6 +115,16 @@ whether or not to display borders outlining the zones. It is possible
 to define an arbitrary number of drop zones as long as their labels
 are unique.
 
+Additionally, you can specify the alignment for items once they are dropped in
+the zone.  No alignment is the default, and causes items to stay where the
+learner drops them.  Left alignment causes dropped items to be placed from left
+to right across the zone. Right alignment causes the items to be placed from
+right to left across the zone. Center alignment places items from top to bottom
+along the center of the zone. If left, right, or center alignment is chosen,
+items dropped in a zone will not overlap, but if the zone is not made large
+enough for all its items, they will overflow the bottom of the zone, and
+potentially, overlap the zones below.
+
 ![Drag item edit](https://raw.githubusercontent.com/edx-solutions/xblock-drag-and-drop-v2/c955a38dc3a1aaf609c586d293ce19b282e11ffd/doc/img/edit-view-items.png)
 
 In the final step, you define the background and text color for drag

drag_and_drop_v2/public/css/drag_and_drop.css

@@ -133,6 +133,8 @@
     display: inline-block;
     width: 100%; /* Make sure size of content never exceeds size of item */
                  /* (this can happen if item displays image whose width exceeds computed max-width of item) */
+    overflow-wrap: break-word;
+    word-wrap: break-word;
 }
 
 /* Placed option */
@@ -142,6 +144,33 @@
     transform: translate(-50%, -50%); /* These blocks are to be centered on their absolute x,y position */
 }
 
+/* Placed options in an aligned zone */
+.xblock--drag-and-drop .zone .item-wrapper {
+    width: 100%;
+    position: relative;
+}
+.xblock--drag-and-drop .zone .item-align .option {
+    transform: none;
+    position: relative;
+    vertical-align: top;
+    margin-right: 2px;
+    margin-bottom: 2px;
+}
+.xblock--drag-and-drop .zone .item-align-left {
+    text-align: left;
+}
+.xblock--drag-and-drop .zone .item-align-right {
+    text-align: right;
+}
+.xblock--drag-and-drop .zone .item-align-center {
+    text-align: center;
+}
+.xblock--drag-and-drop .zone .item-align-center .option {
+    display: block;
+    margin-left: auto;
+    margin-right: auto;
+}
+
 /* Focused option */
 .xblock--drag-and-drop .drag-container .item-bank .option:focus,
 .xblock--drag-and-drop .drag-container .item-bank .option:hover,

drag_and_drop_v2/public/css/drag_and_drop_edit.css

@@ -144,7 +144,7 @@
                                here we make sure that both input fields get the same value for line-height */
 }
 
-.xblock--drag-and-drop--editor .zones-form .zone-row .layout {
+.xblock--drag-and-drop--editor .zones-form .zone-row .alignment {
     margin-bottom: 15px;
 }
 
@@ -160,6 +160,7 @@
     height: 128px;
 }
 
+.xblock--drag-and-drop--editor .zones-form .zones-form-help,
 .xblock--drag-and-drop--editor .target-image-form .target-image-form-help,
 .xblock--drag-and-drop--editor .item-styles-form .item-styles-form-help {
     margin-top: 5px;

drag_and_drop_v2/public/js/drag_and_drop.js

@@ -52,19 +52,18 @@ function DragNDropTemplates(url_name) {
         );
     };
 
-    var getZoneTitle = function(zoneUID, ctx) {
-        // Given the context and a zone UID, return the zone's title
+    var getZone = function(zoneUID, ctx) {
         for (var i = 0; i < ctx.zones.length; i++) {
             if (ctx.zones[i].uid === zoneUID) {
-                return ctx.zones[i].title;
+                return ctx.zones[i];
             }
         }
-        return "Unknown Zone";  // This title should never be seen, so does not need i18n
-    }
+    };
 
     var itemTemplate = function(item, ctx) {
         // Define properties
         var className = (item.class_name) ? item.class_name : "";
+        var zone = getZone(item.zone, ctx) || {};
         if (item.has_image) {
             className += " " + "option-with-image";
         }
@@ -89,12 +88,31 @@ function DragNDropTemplates(url_name) {
             style['outline-color'] = item.color;
         }
         if (item.is_placed) {
+            if (item.zone_align === 'none') {
+                // This is not an "aligned" zone, so the item gets positioned where the learner dropped it.
                 style.left = item.x_percent + "%";
                 style.top = item.y_percent + "%";
-            if (item.widthPercent) {
+                if (item.widthPercent) {  // This item has an author-defined explicit width
                     style.width = item.widthPercent + "%";
-                style.maxWidth = item.widthPercent + "%"; // default maxWidth is ~33%
-            } else if (item.imgNaturalWidth) {
+                    style.maxWidth = item.widthPercent + "%"; // default maxWidth is ~30%
+                }
+            } else {
+                // This is an "aligned" zone, so the item position within the zone is calculated by the browser.
+                // Allow for the input + button width for aligned items
+                if (item.input) {
+                    style.marginRight = '190px';
+                }
+                // Make up for the fact we're in a wrapper container by calculating percentage differences.
+                var maxWidth = (item.widthPercent || 30) / 100;
+                var widthPercent = zone.width_percent / 100;
+                style.maxWidth = ((1 / (widthPercent / maxWidth)) * 100) + '%';
+                if (item.widthPercent) {
+                    style.width = style.maxWidth;
+                }
+            }
+            // Finally, if the item is using automatic sizing and contains an image, we
+            // always prefer the natural width of the image (subject to the max-width):
+            if (item.imgNaturalWidth && !item.widthPercent) {
                 style.width = (item.imgNaturalWidth + 22) + "px"; // 22px is for 10px padding + 1px border each side
                 // ^ Hack to detect image width at runtime and make webkit consistent with Firefox
             }
@@ -126,10 +144,11 @@ function DragNDropTemplates(url_name) {
             // Insert information about zone in which this item has been placed
             var item_description_id = url_name + '-item-' + item.value + '-description';
             item_content.properties.attributes = { 'aria-describedby': item_description_id };
+            var zone_title = (zone.title || "Unknown Zone");  // This "Unknown" text should never be seen, so does not need i18n
             var item_description = h(
                 'div',
                 { id: item_description_id, className: 'sr' },
-                gettext('Correctly placed in: ') + getZoneTitle(item.zone, ctx)
+                gettext('Correctly placed in: ') + zone_title
             );
             children.splice(1, 0, item_description);
         }
@@ -153,6 +172,17 @@ function DragNDropTemplates(url_name) {
     var zoneTemplate = function(zone, ctx) {
         var className = ctx.display_zone_labels ? 'zone-name' : 'zone-name sr';
         var selector = ctx.display_zone_borders ? 'div.zone.zone-with-borders' : 'div.zone';
+
+        // If zone is aligned, mark its item alignment
+        // and render its placed items as children
+        var item_wrapper = 'div.item-wrapper';
+        var items_in_zone = [];
+        if (zone.align !== 'none') {
+            item_wrapper += '.item-align.item-align-' + zone.align;
+            var is_item_in_zone = function(i) { return i.is_placed && (i.zone === zone.uid); };
+            items_in_zone = $.grep(ctx.items, is_item_in_zone);
+        }
+
         return (
             h(
                 selector,
@@ -163,6 +193,8 @@ function DragNDropTemplates(url_name) {
                         'dropzone': 'move',
                         'aria-dropeffect': 'move',
                         'data-uid': zone.uid,
+                        'data-zone_id': zone.id,
+                        'data-zone_align': zone.align,
                         'role': 'button',
                     },
                     style: {
@@ -172,7 +204,8 @@ function DragNDropTemplates(url_name) {
                 },
                 [
                     h('p', { className: className }, zone.title),
-                    h('p', { className: 'zone-description sr' }, zone.description)
+                    h('p', { className: 'zone-description sr' }, zone.description),
+                    h(item_wrapper, renderCollection(itemTemplate, items_in_zone, ctx))
                 ]
             )
         );
@@ -232,9 +265,13 @@ function DragNDropTemplates(url_name) {
         if (ctx.popup_html && !ctx.last_action_correct) {
             popupSelector += '.popup-incorrect';
         }
+        // Render only items_in_bank and items_placed_unaligned here;
+        // items placed in aligned zones will be rendered by zoneTemplate.
         var is_item_placed = function(i) { return i.is_placed; };
         var items_placed = $.grep(ctx.items, is_item_placed);
         var items_in_bank = $.grep(ctx.items, is_item_placed, true);
+        var is_item_placed_unaligned = function(i) { return i.zone_align === 'none'; };
+        var items_placed_unaligned = $.grep(items_placed, is_item_placed_unaligned);
         return (
             h('section.themed-xblock.xblock--drag-and-drop', [
                 problemTitle,
@@ -271,7 +308,7 @@ function DragNDropTemplates(url_name) {
                             ]
                         ),
                         renderCollection(zoneTemplate, ctx.zones, ctx),
-                        renderCollection(itemTemplate, items_placed, ctx),
+                        renderCollection(itemTemplate, items_placed_unaligned, ctx)
                     ]
                     ),
                 ]),
@@ -335,6 +372,7 @@ function DragAndDropBlock(runtime, element, configuration) {
             state = stateResult[0]; // stateResult is an array of [data, statusText, jqXHR]
             migrateConfiguration(bgImg.width);
             migrateState(bgImg.width, bgImg.height);
+            markItemZoneAlign();
             bgImgNaturalWidth = bgImg.width;
 
             // Set up event handlers:
@@ -596,6 +634,8 @@ function DragAndDropBlock(runtime, element, configuration) {
             $anchor = $zone;
         }
         var zone = String($zone.data('uid'));
+        var zone_id = $zone.data('zone_id');
+        var zone_align = $zone.data('zone_align');
         var $target_img = $root.find('.target-img');
 
         // Calculate the position of the item to place relative to the image.
@@ -606,6 +646,7 @@ function DragAndDropBlock(runtime, element, configuration) {
 
         state.items[item_id] = {
             zone: zone,
+            zone_align: zone_align,
             x_percent: x_pos_percent,
             y_percent: y_pos_percent,
             submitting_location: true,
@@ -879,6 +920,7 @@ function DragAndDropBlock(runtime, element, configuration) {
             if (item_user_state) {
                 itemProperties.is_placed = true;
                 itemProperties.zone = item_user_state.zone;
+                itemProperties.zone_align = item_user_state.zone_align;
                 itemProperties.x_percent = item_user_state.x_percent;
                 itemProperties.y_percent = item_user_state.y_percent;
             }
@@ -963,5 +1005,22 @@ function DragAndDropBlock(runtime, element, configuration) {
         });
     };
 
+    /**
+     * markItemZoneAlign: Mark the items placed in an aligned zone with the zone
+     * alignment, so they can be properly placed inside the zone.
+     * We have do this in JS, not python, since zone configurations may change.
+     */
+    var markItemZoneAlign = function() {
+        var zone_alignments = {};
+        configuration.zones.forEach(function(zone) {
+            if (!zone.align) zone.align = 'none';
+            zone_alignments[zone.uid] = zone.align;
+        });
+        Object.keys(state.items).forEach(function(item_id) {
+            var item = state.items[item_id];
+            item.zone_align = zone_alignments[item.zone] || 'none';
+        });
+    };
+
     init();
 }

drag_and_drop_v2/public/js/drag_and_drop_edit.js

@@ -14,6 +14,12 @@ function DragAndDropEditBlock(runtime, element, params) {
         }
         return Number(value).toFixed(Number(value) == parseInt(value) ? 0 : 1);
     });
+    Handlebars.registerHelper('ifeq', function(v1, v2, options) {
+      if (v1 === v2) {
+        return options.fn(this);
+      }
+      return options.inverse(this);
+    });
 
     var $element = $(element);
 
@@ -172,6 +178,7 @@ function DragAndDropEditBlock(runtime, element, params) {
                         })
                         .on('click', '.remove-zone', _fn.build.form.zone.remove)
                         .on('input', '.zone-row input', _fn.build.form.zone.changedInputHandler)
+                        .on('change', '.align-select', _fn.build.form.zone.changedInputHandler)
                         .on('click', '.target-image-form button', function(e) {
                             e.preventDefault();
 
@@ -240,6 +247,7 @@ function DragAndDropEditBlock(runtime, element, params) {
                                 height: oldZone.height || 100,
                                 x: oldZone.x || 0,
                                 y: oldZone.y || 0,
+                                align: oldZone.align || ''
                             };
 
                             _fn.build.form.zone.zoneObjects.push(zoneObj);
@@ -316,10 +324,12 @@ function DragAndDropEditBlock(runtime, element, params) {
                                         y_percent: (+zoneObj.y) / imgHeight * 100,
                                         width_percent: (+zoneObj.width) / imgWidth * 100,
                                         height_percent: (+zoneObj.height) / imgHeight * 100,
+                                        align: zoneObj.align
                                     })
                                 );
                             });
                         },
+
                         changedInputHandler: function(ev) {
                             // Called when any of the inputs have changed.
                             var $changedInput = $(ev.currentTarget);
@@ -337,6 +347,8 @@ function DragAndDropEditBlock(runtime, element, params) {
                                 record.x = $changedInput.val();
                             } else if ($changedInput.hasClass('y')) {
                                 record.y = $changedInput.val();
+                            } else if ($changedInput.hasClass('align-select')) {
+                                record.align = $changedInput.val();
                             }
                             _fn.build.form.zone.renderZonesPreview();
                         },

drag_and_drop_v2/templates/html/js_templates.html

@@ -51,6 +51,34 @@
                    class="coord y"
                    value="{{ zone.y }}" />
         </div>
+        <div class="alignment">
+            <label for="zone-{{index}}-align">
+                {{i18n "Alignment"}}
+            </label>
+            <select id="zone-{{index}}-align"
+                    class="align-select"
+                    aria-describedby="zone-align-description">
+                <option value="" 
+                    {{#ifeq zone.align ""}}selected{{/ifeq}}>
+                    {{i18n "none"}}
+                </option>
+                <option value="left" 
+                    {{#ifeq zone.align "left"}}selected{{/ifeq}}>
+                    {{i18n "left"}}
+                </option>
+                <option value="center" 
+                    {{#ifeq zone.align "center"}}selected{{/ifeq}}>
+                    {{i18n "center"}}
+                </option>
+                <option value="right"
+                    {{#ifeq zone.align "right"}}selected{{/ifeq}}>
+                    {{i18n "right"}}
+                </option>
+            </select>
+            <div id="zone-align-description" class="zones-form-help">
+                {{i18n "Align dropped items to the left, center, or right.  Default is no alignment (items stay exactly where the user drops them)."}}
+            </div>
+        </div>
     </div>
 </script>
 

tests/integration/data/test_sizing_template.json

@@ -2,16 +2,16 @@
   {% if img == "wide" %}
     "targetImg": "{{img_wide_url}}",
     "zones": [
-      {"title": "Zone 1/3", "width": 533, "height": 200, "x": "0", "y": "0"},
-      {"title": "Zone 50%", "width": 800, "height": 200, "x": "0", "y": "350"},
-      {"title": "Zone 75%", "width": 1200, "height": 200, "x": "0", "y": "700"}
+      {"title": "Zone 1/3", "width": 533, "height": 200, "x": "0", "y": "0" {% if align_zones %}, "align": "left" {% endif %} },
+      {"title": "Zone 50%", "width": 800, "height": 200, "x": "0", "y": "350" {% if align_zones %}, "align": "center" {% endif %} },
+      {"title": "Zone 75%", "width": 1200, "height": 200, "x": "0", "y": "700" {% if align_zones %}, "align": "right" {% endif %} }
     ],
   {% else %}
     "targetImg": "{{img_square_url}}",
     "zones": [
-      {"title": "Zone 1/3", "width": 166, "height": 100, "x": "0", "y": "0"},
-      {"title": "Zone 50%", "width": 250, "height": 100, "x": "0", "y": "200"},
-      {"title": "Zone 75%", "width": 375, "height": 100, "x": "0", "y": "400"}
+      {"title": "Zone 1/3", "width": 166, "height": 100, "x": "0", "y": "0" {% if align_zones %}, "align": "left" {% endif %} },
+      {"title": "Zone 50%", "width": 250, "height": 100, "x": "0", "y": "200" {% if align_zones %}, "align": "center" {% endif %} },
+      {"title": "Zone 75%", "width": 375, "height": 100, "x": "0", "y": "400" {% if align_zones %}, "align": "right" {% endif %} }
     ],
   {% endif %}
   "displayBorders": true,

tests/integration/data/test_zone_align.json

+{
+  "zones": [
+    {
+      "index": 1,
+      "title": "Zone No Align",
+      "width": 200,
+      "height": 100,
+      "x": 0,
+      "y": 0,
+      "align": "",
+      "id": "zone-none"
+    },
+    {
+      "index": 1,
+      "title": "Zone Invalid Align",
+      "width": 200,
+      "height": 100,
+      "x": 0,
+      "y": 100,
+      "align": "invalid",
+      "id": "zone-invalid"
+    },
+    {
+      "index": 2,
+      "title": "Zone Left Align",
+      "width": 200,
+      "height": 100,
+      "x": 0,
+      "y": 200,
+      "align": "left",
+      "id": "zone-left"
+    },
+    {
+      "index": 3,
+      "title": "Zone Right Align",
+      "width": 200,
+      "height": 100,
+      "x": 0,
+      "y": 300,
+      "align": "right",
+      "id": "zone-right"
+    },
+    {
+      "index": 4,
+      "title": "Zone Center Align",
+      "width": 200,
+      "height": 100,
+      "x": 0,
+      "y": 400,
+      "align": "center",
+      "id": "zone-center"
+    }
+  ],
+  "items": [
+    {
+      "displayName": "AAAA",
+      "feedback": {
+        "incorrect": "No",
+        "correct": "Yes"
+      },
+      "zone": "Zone No Align",
+      "imageURL": "",
+      "id": 0
+    },
+    {
+      "displayName": "AAAA",
+      "feedback": {
+        "incorrect": "No",
+        "correct": "Yes"
+      },
+      "zone": "Zone No Align",
+      "imageURL": "",
+      "id": 1
+    },
+    {
+      "displayName": "AAAA",
+      "feedback": {
+        "incorrect": "No",
+        "correct": "Yes"
+      },
+      "zone": "Zone No Align",
+      "imageURL": "",
+      "id": 2
+    },
+    {
+      "displayName": "BBBB",
+      "feedback": {
+        "incorrect": "No",
+        "correct": "Yes"
+      },
+      "zone": "Zone Invalid Align",
+      "imageURL": "",
+      "id": 3
+    },
+    {
+      "displayName": "BBBB",
+      "feedback": {
+        "incorrect": "No",
+        "correct": "Yes"
+      },
+      "zone": "Zone Invalid Align",
+      "imageURL": "",
+      "id": 4
+    },
+    {
+      "displayName": "BBBB",
+      "feedback": {
+        "incorrect": "No",
+        "correct": "Yes"
+      },
+      "zone": "Zone Invalid Align",
+      "imageURL": "",
+      "id": 5
+    },
+    {
+      "displayName": "CCCC",
+      "feedback": {
+        "incorrect": "No",
+        "correct": "Yes"
+      },
+      "zone": "Zone Left Align",
+      "imageURL": "",
+      "id": 6
+    },
+    {
+      "displayName": "CCCC",
+      "feedback": {
+        "incorrect": "No",
+        "correct": "Yes"
+      },
+      "zone": "Zone Left Align",
+      "imageURL": "",
+      "id": 7
+    },
+    {
+      "displayName": "CCCC",
+      "feedback": {
+        "incorrect": "No",
+        "correct": "Yes"
+      },
+      "zone": "Zone Left Align",
+      "imageURL": "",
+      "id": 8
+    },
+    {
+      "displayName": "DDDD",
+      "feedback": {
+        "incorrect": "No",
+        "correct": "Yes"
+      },
+      "zone": "Zone Right Align",
+      "imageURL": "",
+      "id": 9
+    },
+    {
+      "displayName": "DDDD",
+      "feedback": {
+        "incorrect": "No",
+        "correct": "Yes"
+      },
+      "zone": "Zone Right Align",
+      "imageURL": "",
+      "id": 10 
+    },
+    {
+      "displayName": "DDDD",
+      "feedback": {
+        "incorrect": "No",
+        "correct": "Yes"
+      },
+      "zone": "Zone Right Align",
+      "imageURL": "",
+      "id": 11 
+    },
+    {
+      "displayName": "EEEE",
+      "feedback": {
+        "incorrect": "No",
+        "correct": "Yes"
+      },
+      "zone": "Zone Center Align",
+      "imageURL": "",
+      "id": 12 
+    },
+    {
+      "displayName": "EEEE",
+      "feedback": {
+        "incorrect": "No",
+        "correct": "Yes"
+      },
+      "zone": "Zone Center Align",
+      "imageURL": "",
+      "id": 13 
+    },
+    {
+      "displayName": "EEEE",
+      "feedback": {
+        "incorrect": "No",
+        "correct": "Yes"
+      },
+      "zone": "Zone Center Align",
+      "imageURL": "",
+      "id": 14 
+    },
+  ],
+  "feedback": {
+    "start": "Intro",
+    "finish": "Final"
+  },
+}

tests/integration/test_base.py

@@ -91,6 +91,13 @@ class BaseIntegrationTest(SeleniumBaseTest):
     def scroll_down(self, pixels=50):
         self.browser.execute_script("$(window).scrollTop({})".format(pixels))
 
+    def _get_style(self, selector, style, computed=True):
+        if computed:
+            query = 'return getComputedStyle($("{selector}").get(0)).{style}'
+        else:
+            query = 'return $("{selector}").get(0).style.{style}'
+        return self.browser.execute_script(query.format(selector=selector, style=style))
+
     @staticmethod
     def get_element_html(element):
         return element.get_attribute('innerHTML').strip()

tests/integration/test_interaction.py

@@ -137,7 +137,9 @@ class InteractionTestBase(object):
         item = self._get_placed_item_by_value(item_value)
         self.wait_until_visible(item)
         item_content = item.find_element_by_css_selector('.item-content')
+        self.wait_until_visible(item_content)
         item_description = item.find_element_by_css_selector('.sr')
+        self.wait_until_visible(item_description)
         item_description_id = '-item-{}-description'.format(item_value)
 
         self.assertIsNone(item.get_attribute('tabindex'))
@@ -592,3 +594,90 @@ class MultipleBlocksDataInteraction(InteractionTestBase, BaseIntegrationTest):
         # Test mouse and keyboard interaction
         self.interact_with_keyboard_help(scroll_down=900)
         self.interact_with_keyboard_help(scroll_down=0, use_keyboard=True)
+
+
+@ddt
+class ZoneAlignInteractionTest(InteractionTestBase, BaseIntegrationTest):
+    """
+    Verifying Drag and Drop XBlock interactions using zone alignment.
+    """
+    PAGE_TITLE = 'Drag and Drop v2'
+    PAGE_ID = 'drag_and_drop_v2'
+    ACTION_KEYS = (None, Keys.RETURN, Keys.SPACE, Keys.CONTROL+'m', Keys.COMMAND+'m')
+
+    def setUp(self):
+        super(ZoneAlignInteractionTest, self).setUp()
+
+    def _get_scenario_xml(self):
+        return self._get_custom_scenario_xml("data/test_zone_align.json")
+
+    def _assert_zone_align_item(self, item_id, zone_id, align, action_key=None):
+        """
+        Test items placed in a zone with the given align setting.
+        Ensure that they are children of the zone.
+        """
+        # parent container has the expected alignment
+        item_wrapper_selector = "div[data-uid='{zone_id}'] .item-wrapper".format(zone_id=zone_id)
+        self.assertEquals(self._get_style(item_wrapper_selector, 'textAlign'), align)
+
+        # Items placed in zones with align setting are children of the zone
+        zone_item_selector = '{item_wrapper_selector} .option'.format(item_wrapper_selector=item_wrapper_selector)
+        prev_placed_items = self._page.find_elements_by_css_selector(zone_item_selector)
+
+        self.place_item(item_id, zone_id, action_key)
+        placed_items = self._page.find_elements_by_css_selector(zone_item_selector)
+        self.assertEquals(len(placed_items), len(prev_placed_items) + 1)
+
+        # Not children of the target
+        target_item = '.target > .option'
+        self.assertEquals(len(self._page.find_elements_by_css_selector(target_item)), 0)
+
+        # Aligned items are relative positioned, with no transform or top/left
+        self.assertEquals(self._get_style(zone_item_selector, 'position'), 'relative')
+        self.assertEquals(self._get_style(zone_item_selector, 'transform'), 'none')
+        self.assertEquals(self._get_style(zone_item_selector, 'left'), '0px')
+        self.assertEquals(self._get_style(zone_item_selector, 'top'), '0px')
+
+        # Center-aligned items are display block
+        if align == 'center':
+            self.assertEquals(self._get_style(zone_item_selector, 'display'), 'block')
+        # but other aligned items are just inline-block
+        else:
+            self.assertEquals(self._get_style(zone_item_selector, 'display'), 'inline-block')
+
+    def test_no_zone_align(self):
+        """
+        Test items placed in a zone with no align setting.
+        Ensure that they are children of div.target, not the zone.
+        """
+        zone_id = "Zone No Align"
+        self.place_item(0, zone_id)
+        zone_item_selector = "div[data-uid='{zone_id}'] .item-wrapper .option".format(zone_id=zone_id)
+        self.assertEquals(len(self._page.find_elements_by_css_selector(zone_item_selector)), 0)
+
+        target_item_selector = '.target > .option'
+        placed_items = self._page.find_elements_by_css_selector(target_item_selector)
+        self.assertEquals(len(placed_items), 1)
+        self.assertEquals(placed_items[0].get_attribute('data-value'), '0')
+
+        # Non-aligned items are absolute positioned, with top/bottom set to px
+        self.assertEquals(self._get_style(target_item_selector, 'position'), 'absolute')
+        self.assertRegexpMatches(self._get_style(target_item_selector, 'left'), r'^\d+(\.\d+)?px$')
+        self.assertRegexpMatches(self._get_style(target_item_selector, 'top'), r'^\d+(\.\d+)?px$')
+
+    @data(
+        ([3, 4, 5], "Zone Invalid Align", "start"),
+        ([6, 7, 8], "Zone Left Align", "left"),
+        ([9, 10, 11], "Zone Right Align", "right"),
+        ([12, 13, 14], "Zone Center Align", "center"),
+    )
+    @unpack
+    def test_zone_align(self, items, zone, alignment):
+        reset = self._get_reset_button()
+        for item in items:
+            for action_key in self.ACTION_KEYS:
+                self._assert_zone_align_item(item, zone, alignment, action_key)
+                # Reset exercise
+                self.scroll_down(pixels=200)
+                reset.click()
+                self.scroll_down(pixels=0)

tests/integration/test_render.py

@@ -65,13 +65,6 @@ class TestDragAndDropRender(BaseIntegrationTest):
         self.browser.get(self.live_server_url)
         self._page = self.go_to_page(self.PAGE_TITLE)
 
-    def _get_style(self, selector, style, computed=True):
-        if computed:
-            query = 'return getComputedStyle($("{selector}").get(0)).{style}'
-        else:
-            query = 'return $("{selector}").get(0).style.{style}'
-        return self.browser.execute_script(query.format(selector=selector, style=style))
-
     def _assert_box_percentages(self, selector, left, top, width, height):
         """ Assert that the element 'selector' has the specified position/size percentages """
         values = {key: self._get_style(selector, key, False) for key in ['left', 'top', 'width', 'height']}
@@ -188,6 +181,7 @@ class TestDragAndDropRender(BaseIntegrationTest):
             self.assertEqual(zone.get_attribute('dropzone'), 'move')
             self.assertEqual(zone.get_attribute('aria-dropeffect'), 'move')
             self.assertEqual(zone.get_attribute('data-uid'), 'Zone {}'.format(zone_number))
+            self.assertEqual(zone.get_attribute('data-zone_align'), 'none')
             self.assertIn('ui-droppable', self.get_element_classes(zone))
             zone_box_percentages = box_percentages[index]
             self._assert_box_percentages(  # pylint: disable=star-args
@@ -272,3 +266,31 @@ class TestDragAndDropRender(BaseIntegrationTest):
         for zone in zones:
             zone_name = zone.find_element_by_css_selector('p.zone-name')
             self.assertNotIn('sr', zone_name.get_attribute('class'))
+
+
+@ddt
+class TestDragAndDropRenderZoneAlign(BaseIntegrationTest):
+    """
+    Verifying Drag and Drop XBlock rendering using zone alignment.
+    """
+    PAGE_TITLE = 'Drag and Drop v2'
+    PAGE_ID = 'drag_and_drop_v2'
+
+    def setUp(self):
+        super(TestDragAndDropRenderZoneAlign, self).setUp()
+        scenario_xml = self._get_custom_scenario_xml("data/test_zone_align.json")
+        self._add_scenario(self.PAGE_ID, self.PAGE_TITLE, scenario_xml)
+        self._page = self.go_to_page(self.PAGE_TITLE)
+
+    def test_zone_align(self):
+        expected_alignments = {
+            "#-Zone_No_Align": "start",
+            "#-Zone_Invalid_Align": "start",
+            "#-Zone_Left_Align": "left",
+            "#-Zone_Right_Align": "right",
+            "#-Zone_Center_Align": "center"
+        }
+        for zone_id, expected_alignment in expected_alignments.items():
+            selector = "{zone_id} .item-wrapper".format(zone_id=zone_id)
+            self.assertEquals(self._get_style(selector, "textAlign"), expected_alignment)
+            self.assertEquals(self._get_style(selector, "textAlign", computed=True), expected_alignment)

tests/integration/test_sizing.py

@@ -48,9 +48,10 @@ class SizingTests(InteractionTestBase, BaseIntegrationTest):
     """
     PAGE_TITLE = 'Drag and Drop v2 Sizing'
     PAGE_ID = 'drag_and_drop_v2_sizing'
+    ALIGN_ZONES = False  # Set to True to test the feature that aligns draggable items when dropped.
 
-    @staticmethod
-    def _get_scenario_xml():
+    @classmethod
+    def _get_scenario_xml(cls):
         """
         Set up the test scenario:
             * An upper dndv2 xblock with a wide image (1600x900 SVG)
@@ -62,6 +63,7 @@ class SizingTests(InteractionTestBase, BaseIntegrationTest):
         """
         params = {
             "img": "wide",
+            "align_zones": cls.ALIGN_ZONES,
             "img_wide_url": _svg_to_data_uri('dnd-bg-wide.svg'),
             "img_square_url": _svg_to_data_uri('dnd-bg-square.svg'),
             "img_400x300_url": _svg_to_data_uri('400x300.svg'),
@@ -238,6 +240,18 @@ class SizingTests(InteractionTestBase, BaseIntegrationTest):
                 )
 
 
+class AlignedSizingTests(SizingTests):
+    """
+    Run the same tests as SizingTests, but with aligned zones.
+
+    The sizing of draggable items should be consistent when the "align" feature
+    of each zone is enabled. (This is the feature that aligns draggable items
+    once they're placed, rather than keeping them exactly where they were
+    dropped.)
+    """
+    ALIGN_ZONES = True
+
+
 class SizingBackwardsCompatibilityTests(InteractionTestBase, BaseIntegrationTest):
     """
     Test backwards compatibility with data generated in older versions of this block.