Add new component for log buttons

Separate the component that handles scrolling from the component
that displays logs. Put component is log viewer.

Add new related specs.

ee/app/assets/javascripts/logs/components/environment_logs.vue

 <script>
 import { mapActions, mapState, mapGetters } from 'vuex';
-import { GlDropdown, GlDropdownItem, GlFormGroup, GlButton, GlTooltipDirective } from '@gitlab/ui';
-import {
-  canScroll,
-  isScrolledToTop,
-  isScrolledToBottom,
-  scrollDown,
-  scrollUp,
-} from '~/lib/utils/scroll_utils';
-import Icon from '~/vue_shared/components/icon.vue';
+import { GlDropdown, GlDropdownItem, GlFormGroup } from '@gitlab/ui';
+import { scrollDown } from '~/lib/utils/scroll_utils';
+import LogControlButtons from './log_control_buttons.vue';
 
 export default {
   components: {
     GlDropdown,
     GlDropdownItem,
     GlFormGroup,
-    GlButton,
-    Icon,
-  },
-  directives: {
-    GlTooltip: GlTooltipDirective,
+    LogControlButtons,
   },
   props: {
     environmentId: {
@@ -46,12 +36,6 @@ export default {
       default: '',
     },
   },
-  data() {
-    return {
-      scrollToTopEnabled: false,
-      scrollToBottomEnabled: false,
-    };
-  },
   computed: {
     ...mapState('environmentLogs', ['environments', 'logs', 'pods']),
     ...mapGetters('environmentLogs', ['trace']),
@@ -63,16 +47,12 @@ export default {
     trace(val) {
       this.$nextTick(() => {
         if (val) {
-          this.scrollDown();
-        } else {
-          this.updateScrollState();
+          scrollDown();
         }
+        this.$refs.scrollButtons.update();
       });
     },
   },
-  created() {
-    window.addEventListener('scroll', this.updateScrollState);
-  },
   mounted() {
     this.setInitData({
       projectPath: this.projectFullPath,
@@ -82,17 +62,8 @@ export default {
 
     this.fetchEnvironments(this.environmentsPath);
   },
-  destroyed() {
-    window.removeEventListener('scroll', this.updateScrollState);
-  },
   methods: {
     ...mapActions('environmentLogs', ['setInitData', 'showPodLogs', 'fetchEnvironments']),
-    updateScrollState() {
-      this.scrollToTopEnabled = canScroll() && !isScrolledToTop();
-      this.scrollToBottomEnabled = canScroll() && !isScrolledToBottom();
-    },
-    scrollUp,
-    scrollDown,
   },
 };
 </script>
@@ -147,48 +118,12 @@ export default {
           </gl-dropdown>
         </gl-form-group>
       </div>
-      <div class="controllers align-self-end">
-        <div
-          v-gl-tooltip
-          class="controllers-buttons"
-          :title="__('Scroll to top')"
-          aria-labelledby="scroll-to-top"
-        >
-          <gl-button
-            id="scroll-to-top"
-            class="btn-blank js-scroll-to-top"
-            :aria-label="__('Scroll to top')"
-            :disabled="!scrollToTopEnabled"
-            @click="scrollUp()"
-            ><icon name="scroll_up"
-          /></gl-button>
-        </div>
-        <div
-          v-gl-tooltip
-          class="controllers-buttons"
-          :title="__('Scroll to bottom')"
-          aria-labelledby="scroll-to-bottom"
-        >
-          <gl-button
-            id="scroll-to-bottom"
-            class="btn-blank js-scroll-to-bottom"
-            :aria-label="__('Scroll to bottom')"
-            :disabled="!scrollToBottomEnabled"
-            @click="scrollDown()"
-            ><icon name="scroll_down"
-          /></gl-button>
-        </div>
-        <gl-button
-          id="refresh-log"
-          v-gl-tooltip
-          class="ml-1 px-2 js-refresh-log"
-          :title="__('Refresh')"
-          :aria-label="__('Refresh')"
-          @click="showPodLogs(pods.current)"
-        >
-          <icon name="retry" />
-        </gl-button>
-      </div>
+
+      <log-control-buttons
+        ref="scrollButtons"
+        class="controllers align-self-end"
+        @refresh="showPodLogs(pods.current)"
+      />
     </div>
     <pre class="build-trace js-log-trace"><code class="bash">{{trace}}
       <div v-if="showLoader" class="build-loader-animation js-build-loader-animation">

ee/app/assets/javascripts/logs/components/log_control_buttons.vue

+<script>
+import { GlButton, GlTooltipDirective } from '@gitlab/ui';
+import {
+  canScroll,
+  isScrolledToTop,
+  isScrolledToBottom,
+  scrollDown,
+  scrollUp,
+} from '~/lib/utils/scroll_utils';
+import Icon from '~/vue_shared/components/icon.vue';
+
+export default {
+  components: {
+    Icon,
+    GlButton,
+  },
+  directives: {
+    GlTooltip: GlTooltipDirective,
+  },
+  data() {
+    return {
+      scrollToTopEnabled: false,
+      scrollToBottomEnabled: false,
+    };
+  },
+  created() {
+    window.addEventListener('scroll', this.update);
+  },
+  destroyed() {
+    window.removeEventListener('scroll', this.update);
+  },
+  methods: {
+    /**
+     * Checks if page can be scrolled and updates
+     * enabled/disabled state of buttons accordingly
+     */
+    update() {
+      this.scrollToTopEnabled = canScroll() && !isScrolledToTop();
+      this.scrollToBottomEnabled = canScroll() && !isScrolledToBottom();
+    },
+    handleRefreshClick() {
+      this.$emit('refresh');
+    },
+    scrollUp,
+    scrollDown,
+  },
+};
+</script>
+
+<template>
+  <div>
+    <div
+      v-gl-tooltip
+      class="controllers-buttons"
+      :title="__('Scroll to top')"
+      aria-labelledby="scroll-to-top"
+    >
+      <gl-button
+        id="scroll-to-top"
+        class="btn-blank js-scroll-to-top"
+        :aria-label="__('Scroll to top')"
+        :disabled="!scrollToTopEnabled"
+        @click="scrollUp()"
+        ><icon name="scroll_up"
+      /></gl-button>
+    </div>
+    <div
+      v-gl-tooltip
+      class="controllers-buttons"
+      :title="__('Scroll to bottom')"
+      aria-labelledby="scroll-to-bottom"
+    >
+      <gl-button
+        id="scroll-to-bottom"
+        class="btn-blank js-scroll-to-bottom"
+        :aria-label="__('Scroll to bottom')"
+        :disabled="!scrollToBottomEnabled"
+        @click="scrollDown()"
+        ><icon name="scroll_down"
+      /></gl-button>
+    </div>
+    <gl-button
+      id="refresh-log"
+      v-gl-tooltip
+      class="ml-1 px-2 js-refresh-log"
+      :title="__('Refresh')"
+      :aria-label="__('Refresh')"
+      @click="handleRefreshClick"
+    >
+      <icon name="retry" />
+    </gl-button>
+  </div>
+</template>

ee/spec/frontend/logs/components/environment_logs_spec.js

 import Vue from 'vue';
-import { GlDropdown, GlButton, GlDropdownItem } from '@gitlab/ui';
+import { GlDropdown, GlDropdownItem } from '@gitlab/ui';
 import { shallowMount } from '@vue/test-utils';
-import {
-  canScroll,
-  isScrolledToTop,
-  isScrolledToBottom,
-  scrollDown,
-  scrollUp,
-} from '~/lib/utils/scroll_utils';
+import { scrollDown } from '~/lib/utils/scroll_utils';
 import EnvironmentLogs from 'ee/logs/components/environment_logs.vue';
+
 import { createStore } from 'ee/logs/stores';
 import {
   mockProjectPath,
@@ -30,8 +25,8 @@ describe('EnvironmentLogs', () => {
   let state;
 
   const propsData = {
-    environmentId: mockEnvId,
     projectFullPath: mockProjectPath,
+    environmentId: mockEnvId,
     currentEnvironmentName: mockEnvName,
     environmentsPath: mockEnvironmentsEndpoint,
   };
@@ -42,11 +37,11 @@ describe('EnvironmentLogs', () => {
     fetchEnvironments: jest.fn(),
   };
 
+  const updateControlBtnsMock = jest.fn();
+
   const findEnvironmentsDropdown = () => wrapper.find('.js-environments-dropdown');
   const findPodsDropdown = () => wrapper.find('.js-pods-dropdown');
-  const findScrollToTop = () => wrapper.find('.js-scroll-to-top');
-  const findScrollToBottom = () => wrapper.find('.js-scroll-to-bottom');
-  const findRefreshLog = () => wrapper.find('.js-refresh-log');
+  const findLogControlButtons = () => wrapper.find({ name: 'log-control-buttons-stub' });
   const findLogTrace = () => wrapper.find('.js-log-trace');
 
   const initWrapper = () => {
@@ -55,6 +50,15 @@ describe('EnvironmentLogs', () => {
       sync: false,
       propsData,
       store,
+      stubs: {
+        LogControlButtons: {
+          name: 'log-control-buttons-stub',
+          template: '<div/>',
+          methods: {
+            update: updateControlBtnsMock,
+          },
+        },
+      },
       methods: {
         ...actionMocks,
       },
@@ -78,15 +82,12 @@ describe('EnvironmentLogs', () => {
 
     expect(wrapper.isVueInstance()).toBe(true);
     expect(wrapper.isEmpty()).toBe(false);
+    expect(findLogTrace().isEmpty()).toBe(false);
 
     expect(findEnvironmentsDropdown().is(GlDropdown)).toBe(true);
     expect(findPodsDropdown().is(GlDropdown)).toBe(true);
 
-    expect(findScrollToTop().is(GlButton)).toBe(true);
-    expect(findScrollToBottom().is(GlButton)).toBe(true);
-    expect(findRefreshLog().is(GlButton)).toBe(true);
-
-    expect(findLogTrace().isEmpty()).toBe(false);
+    expect(findLogControlButtons().exists()).toBe(true);
   });
 
   it('mounted inits data', () => {
@@ -129,6 +130,10 @@ describe('EnvironmentLogs', () => {
       expect(findPodsDropdown().findAll(GlDropdownItem).length).toBe(0);
     });
 
+    it('does not update buttons state', () => {
+      expect(updateControlBtnsMock).not.toHaveBeenCalled();
+    });
+
     it('shows a logs trace', () => {
       expect(findLogTrace().text()).toBe('');
       expect(
@@ -164,7 +169,7 @@ describe('EnvironmentLogs', () => {
 
     afterEach(() => {
       scrollDown.mockReset();
-      scrollUp.mockReset();
+      updateControlBtnsMock.mockReset();
 
       actionMocks.setInitData.mockReset();
       actionMocks.showPodLogs.mockReset();
@@ -201,6 +206,10 @@ describe('EnvironmentLogs', () => {
       expect(trace.text().split('\n')).toEqual(mockLines);
     });
 
+    it('update control buttons state', () => {
+      expect(updateControlBtnsMock).toHaveBeenCalledTimes(1);
+    });
+
     it('scrolls to bottom when loaded', () => {
       expect(scrollDown).toHaveBeenCalledTimes(1);
     });
@@ -221,62 +230,11 @@ describe('EnvironmentLogs', () => {
       it('refresh button, trace is refreshed', () => {
         expect(actionMocks.showPodLogs).toHaveBeenCalledTimes(0);
 
-        findRefreshLog().vm.$emit('click');
+        findLogControlButtons().vm.$emit('refresh');
 
         expect(actionMocks.showPodLogs).toHaveBeenCalledTimes(1);
         expect(actionMocks.showPodLogs).toHaveBeenLastCalledWith(mockPodName);
       });
-
-      describe('when scrolling actions are enabled', () => {
-        beforeEach(done => {
-          // mock scrolled to the middle of a long page
-          canScroll.mockReturnValue(true);
-          isScrolledToBottom.mockReturnValue(false);
-          isScrolledToTop.mockReturnValue(false);
-
-          initWrapper();
-          wrapper.vm.updateScrollState();
-          wrapper.vm.$nextTick(done);
-        });
-
-        afterEach(() => {
-          canScroll.mockReset();
-          isScrolledToTop.mockReset();
-          isScrolledToBottom.mockReset();
-        });
-
-        it('click on "scroll to top" scrolls up', () => {
-          expect(findScrollToTop().is('[disabled]')).toBe(false);
-          findScrollToTop().vm.$emit('click');
-          expect(scrollUp).toHaveBeenCalledTimes(1);
-        });
-
-        it('click on "scroll to bottom" scrolls down', () => {
-          expect(findScrollToBottom().is('[disabled]')).toBe(false);
-          findScrollToBottom().vm.$emit('click');
-          expect(scrollDown).toHaveBeenCalledTimes(2); // plus one time when trace was loaded
-        });
-      });
-
-      describe('when scrolling actions are disabled', () => {
-        beforeEach(() => {
-          // mock a short page without a scrollbar
-          canScroll.mockReturnValue(false);
-          isScrolledToBottom.mockReturnValue(true);
-          isScrolledToTop.mockReturnValue(true);
-
-          initWrapper();
-        });
-
-        it('buttons are disabled', done => {
-          wrapper.vm.updateScrollState();
-          wrapper.vm.$nextTick(() => {
-            expect(findScrollToTop().is('[disabled]')).toBe(true);
-            expect(findScrollToBottom().is('[disabled]')).toBe(true);
-            done();
-          });
-        });
-      });
     });
   });
 });

ee/spec/frontend/logs/components/log_control_buttons_spec.js

+import { shallowMount } from '@vue/test-utils';
+import { GlButton } from '@gitlab/ui';
+import {
+  canScroll,
+  isScrolledToTop,
+  isScrolledToBottom,
+  scrollDown,
+  scrollUp,
+} from '~/lib/utils/scroll_utils';
+
+import LogControlButtons from 'ee/logs/components/log_control_buttons.vue';
+
+jest.mock('~/lib/utils/scroll_utils');
+
+describe('LogControlButtons', () => {
+  let wrapper;
+
+  const findScrollToTop = () => wrapper.find('.js-scroll-to-top');
+  const findScrollToBottom = () => wrapper.find('.js-scroll-to-bottom');
+  const findRefreshBtn = () => wrapper.find('.js-refresh-log');
+
+  const initWrapper = () => {
+    wrapper = shallowMount(LogControlButtons, {
+      attachToDocument: true,
+      sync: false,
+    });
+  };
+
+  afterEach(() => {
+    if (wrapper) {
+      wrapper.destroy();
+    }
+  });
+
+  it('displays UI elements', () => {
+    initWrapper();
+
+    expect(wrapper.isVueInstance()).toBe(true);
+    expect(wrapper.isEmpty()).toBe(false);
+
+    expect(findScrollToTop().is(GlButton)).toBe(true);
+    expect(findScrollToBottom().is(GlButton)).toBe(true);
+    expect(findRefreshBtn().is(GlButton)).toBe(true);
+  });
+
+  it('emits a `refresh` event on click on `refersh` button', () => {
+    initWrapper();
+
+    expect(wrapper.emitted('refresh')).toHaveLength(0);
+
+    findRefreshBtn().vm.$emit('click');
+
+    expect(wrapper.emitted('refresh')).toHaveLength(1);
+  });
+
+  describe('when scrolling actions are enabled', () => {
+    beforeEach(() => {
+      // mock scrolled to the middle of a long page
+      canScroll.mockReturnValue(true);
+      isScrolledToBottom.mockReturnValue(false);
+      isScrolledToTop.mockReturnValue(false);
+
+      initWrapper();
+      wrapper.vm.update();
+      return wrapper.vm.$nextTick();
+    });
+
+    afterEach(() => {
+      canScroll.mockReset();
+      isScrolledToTop.mockReset();
+      isScrolledToBottom.mockReset();
+    });
+
+    it('click on "scroll to top" scrolls up', () => {
+      expect(findScrollToTop().is('[disabled]')).toBe(false);
+
+      findScrollToTop().vm.$emit('click');
+
+      expect(scrollUp).toHaveBeenCalledTimes(1);
+    });
+
+    it('click on "scroll to bottom" scrolls down', () => {
+      expect(findScrollToBottom().is('[disabled]')).toBe(false);
+
+      findScrollToBottom().vm.$emit('click');
+
+      expect(scrollDown).toHaveBeenCalledTimes(1); // plus one time when trace was loaded
+    });
+  });
+
+  describe('when scrolling actions are disabled', () => {
+    beforeEach(() => {
+      // mock a short page without a scrollbar
+      canScroll.mockReturnValue(false);
+      isScrolledToBottom.mockReturnValue(true);
+      isScrolledToTop.mockReturnValue(true);
+
+      initWrapper();
+    });
+
+    it('buttons are disabled', () => {
+      wrapper.vm.update();
+      return wrapper.vm.$nextTick(() => {
+        expect(findScrollToTop().is('[disabled]')).toBe(true);
+        expect(findScrollToBottom().is('[disabled]')).toBe(true);
+      });
+    });
+  });
+});