Start using /list_tests to populate subtest menus in test-picker

dashboard/dashboard/elements/test-picker.html

Index: dashboard/dashboard/elements/test-picker.html
diff --git a/dashboard/dashboard/elements/test-picker.html b/dashboard/dashboard/elements/test-picker.html
index 770e073a41ac9a369c9659ca24f0feec0c604d5e..139bf073f84bb9c8ba15a98bf3f801c373d5f986 100644
--- a/dashboard/dashboard/elements/test-picker.html
+++ b/dashboard/dashboard/elements/test-picker.html
@@ -13,6 +13,8 @@ found in the LICENSE file.
 <link rel="import" href="/dashboard/elements/autocomplete-box.html">
 <link rel="import" href="/dashboard/static/simple_xhr.html">
 
+<link rel="import" href="/tracing/base/base.html">
+
 <dom-module id="test-picker">
   <template>
     <style include="iron-flex iron-flex-alignment">
@@ -101,6 +103,48 @@ found in the LICENSE file.
   <script>
     'use strict';
 
+    // TODO(eakuefner): https://github.com/catapult-project/catapult/issues/3441
+    tr.exportTo('d', function() {
+      class Subtests {
+        constructor() {
+          this.subtests_ = new Map();
+        }
+
+        // TODO(eakuefner): implemement cancellation by wrapping
+        async getSubtestsForPath(path) {
+          if (this.subtests_.has(path)) {
+            return await this.subtests_.get(path);
+          }
+
+          const params = {
+            type: 'pattern'
+          };
+          params.p = `${path}/*`;
+          const fullSubtests = await simple_xhr.asPromise(
+              '/list_tests', params);
+          // TODO(eakuefner): Standardize logic for dealing with test paths on
+          // the client side. See
+          // https://github.com/catapult-project/catapult/issues/3443.
+          const subtests = [];
+          for (const fullSubtest of fullSubtests) {
+            subtests.push({
+              name: fullSubtest.substring(fullSubtest.lastIndexOf('/') + 1)});
+          }
+
+          this.subtests_[path] = subtests;
+          return subtests;
+        }
+
+        prepopulate(obj) {
+          for (const [path, subtests] of obj) {
+            this.subtests_.set(path, Promise.resolve(subtests));
+          }
+        }
+      }
+
+      return {Subtests};
+    });
+
     Polymer({
 
       is: 'test-picker',
@@ -154,6 +198,11 @@ found in the LICENSE file.
           ])
         },
 
+        subtests: {
+          type: Object,
+          value: () => new d.Subtests()
+        },
+
         xsrfToken: { notify: true }
 
       },
@@ -253,8 +302,6 @@ found in the LICENSE file.
         } else if (boxIndex == 0) {
           this.updateTestSuiteDescription();
           this.updateBotMenu();
-        } else if (boxIndex == 1) {
-          this.sendSubtestRequest();
         } else {
           // Update all the next dropdown menus for subtests.
           this.updateSubtestMenus(boxIndex + 1);
@@ -288,10 +335,9 @@ found in the LICENSE file.
         var botItems = this.getBotItems();
         menu.set('items', botItems);
         menu.set('disabled', botItems.length === 0);
-        this.subtestDict = null;
-        // If there's a selection, send a subtest request.
+        // If there's a selection, update the subtest menus.
         if (menu.selectedItem) {
-          this.sendSubtestRequest();
+          this.updateSubtestMenus(2);
         } else {
           // Clear all subtest menus.
           this.splice('selectionModels', 2);
@@ -300,84 +346,43 @@ found in the LICENSE file.
       },
 
       /**
-       * Sends a request for subtestDict base on selected test suite and bot.
-       */
-      sendSubtestRequest: function() {
-        if (this.subtestXhr) {
-          this.subtestXhr.abort();
-          this.subtestXhr = null;
-        }
-        var bot = this.getCheckedBot();
-        // If no bot is selected, just leave the current subtests.
-        if (bot === null) {
-          return;
-        }
-        var suite = this.getCheckedSuite();
-        if (!suite) {
-          return;
-        }
-
-        this.loading = true;
-
-        var params = {
-          type: 'sub_tests',
-          suite: suite,
-          bots: bot,
-          xsrf_token: this.xsrfToken
-        };
-        this.subtestXhr = simple_xhr.send(
-            '/list_tests',
-            params,
-            function(response) {
-              this.loading = false;
-              this.subtestDict = response;
-              // Start at first subtest menu.
-              this.updateSubtestMenus(2);
-            }.bind(this),
-            function(error) {
-              // TODO: Display error.
-              this.loading = false;
-            }.bind(this)
-        );
-      },
-
-      /**
        * Updates all subtest menus starting at 'startIndex'.
        */
-      updateSubtestMenus: function(startIndex) {
-        var subtestDict = this.getSubtestAtIndex(startIndex);
-
+      updateSubtestMenus: async function(startIndex) {
+        let subtests = await this.subtests.getSubtestsForPath(
+            this.getCurrentSelectedPathUpTo(startIndex - 1));
         // Update existing subtest menu.
         for (var i = startIndex; i < this.selectionModels.length; i++) {
-          // Remove the rest of the menu if no subtestDict.
-          if (!subtestDict || Object.keys(subtestDict).length == 0) {
+          // Remove the rest of the menu if no subtests.
+          if (subtests === []) {
             this.splice('selectionModels', i);
             this.updateAddButtonState();
             return;
           }
-          var subtestItems = this.getSubtestItems(subtestDict);
-          var menu = this.getSelectionMenu(i);
-          menu.set('items', subtestItems);
+          const menu = this.getSelectionMenu(i);
+          menu.set('items', subtests);
 
           // If there are selected item, update next menu.
           if (menu.selectedItem) {
-            subtestDict = subtestDict[menu.selectedName]['sub_tests'];
+            subtests = await this.subtests.getSubtestsForPath(
+                this.getCurrentSelectedPathUpTo(i - 1, false));
           } else {
-            subtestDict = null;
+            subtests = [];
           }
         }
 
-        // Check if we still need to add a subtest menu.
-        if (subtestDict && Object.keys(subtestDict).length > 0) {
-          var subtestItems = this.getSubtestItems(subtestDict);
+        // If we reached the last iteration but still have subtests, that means
+        // that means that the last extant subtest selection still has subtests
+        // and we need to put those in a new menu.
+        if (subtests !== []) {
           this.push('selectionModels', {
             placeholder: this.SUBTEST_LABEL,
-            datalist: subtestItems,
+            datalist: subtests,
             disabled: false,
           });
           Polymer.dom.flush();
-          var menu = this.getSelectionMenu(this.selectionModels.length - 1);
-          menu.set('items', subtestItems);
+          const menu = this.getSelectionMenu(this.selectionModels.length - 1);
+          menu.set('items', subtests);
         }
 
         this.updateAddButtonState();
@@ -387,32 +392,6 @@ found in the LICENSE file.
         this.enableAddSeries = this.getCurrentSelection() instanceof Array;
       },
 
-      getSubtestAtIndex: function(index) {
-        var subtestDict = this.subtestDict;
-        for (var i = 2; i < index; i++) {
-          var test = this.getSelectionMenu(i).selectedName;
-          if (test in subtestDict) {
-            subtestDict = subtestDict[test]['sub_tests'];
-          } else {
-            return null;
-          }
-        }
-        return subtestDict;
-      },
-
-      getSubtestItems: function(subtestDict) {
-        var subtestItems = [];
-        var subtestNames = Object.keys(subtestDict).sort();
-        for (var i = 0; i < subtestNames.length; i++) {
-          var name = subtestNames[i];
-          subtestItems.push({
-            name: name,
-            tag: (subtestDict[name]['deprecated'] ? this.DEPRECATED_TAG : '')
-          });
-        }
-        return subtestItems;
-      },
-
       getCheckedBot: function() {
         var botMenu = this.getSelectionMenu(1);
         if (botMenu.selectedItem) {
@@ -458,14 +437,27 @@ found in the LICENSE file.
        * is a valid selection.
        */
       getCurrentSelection: function() {
-        var level = 0;
-        var parts = [];
+        const path = this.getCurrentSelectedPathUpTo(-1, true);
+
+        if (this.currentSelectedPath_ === path) {
+          return this.currentSelectedTests_;
+        }
+        this.sendListTestsRequest(path);
+        return null;
+      },
+
+      getCurrentSelectedPathUpTo: function(maxLevel, onlyValid) {
+        let level = 0;
+        const parts = [];
         while (true) {
-          var menu = this.getSelectionMenu(level);
-          if (!menu || !menu.selectedItem) {
+          if (maxLevel !== -1 && level <= maxLevel) {
+            break;
+          }
+          const menu = this.getSelectionMenu(level);
+          if (onlyValid && (!menu || !menu.selectedItem)) {
             // A selection is only valid if it specifies at least one subtest
             // component, which is the third level.
-            if (level <= 2) return null;
+            if (level <= 2) return undefined;
             break;
           } else {
             // We want to collect all the subtest components so we can form
@@ -475,17 +467,12 @@ found in the LICENSE file.
           level += 1;
         }
 
-        var suite = this.getSelectionMenu(0).selectedItem.name;
-        var bot = this.getCheckedBot();
+        const suite = this.getSelectionMenu(0).selectedItem.name;
+        const bot = this.getCheckedBot();
         parts.unshift(suite);
         parts.unshift(bot);
 
-        var path = parts.join('/');
-
-        if (this.currentSelectedPath_ === path)
-          return this.currentSelectedTests_;
-        this.sendListTestsRequest(path);
-        return null;
+        return parts.join('/');
       },
 
       getCurrentSelectedPath: function() {