Added functional tests for scatterplot facets

* Added test for scatterplots
* Enriched test docs with a section on visual testing

Co-authored-by: Kush Trivedi <44091822+kushthedude@users.noreply.github.com>

docs/docs/technical-reference/functional-tests.md

@@ -94,10 +94,10 @@ A typical OpenRefine test starts with the following code
 
 ```javascript
 it('Ensure cells are blanked down', function () {
-    cy.loadAndVisitProject('food.mini')
+  cy.loadAndVisitProject('food.mini');
-    cy.get('.viewpanel-sorting a').contains('Sort').click()
+  cy.get('.viewpanel-sorting a').contains('Sort').click();
-    cy.get('.viewpanel').should('to.contain', 'Something')
+  cy.get('.viewpanel').should('to.contain', 'Something');
-})
+});
 ```
 
 The first noticeable thing about a test is the description (`Ensure cells are blanked down`), which describes what the test is doing.  
@@ -145,8 +145,8 @@ The fixture parameter can be
     ['0A', '0B', '0C'],
     ['1A', '1B', '1C'],
     ['2A', '2B', '2C'],
-    ]
+  ];
-    cy.loadAndVisitProject(fixture)
+  cy.loadAndVisitProject(fixture);
   ```
 
 - A referenced dataset: `food.small` or `food.mini`  
@@ -194,6 +194,35 @@ You can pass variables at the command-line level
 yarn --cwd ./main/tests/cypress run cypress open --env OPENREFINE_URL="http://localhost:1234"
 ```
 
+### Visual testing
+
+Tests generally ensure application behavior by making assertions against the DOM, to ensure specific texts or css attributes are present in the document body.  
+Visual testing, on the contrary, is a way to test applications by comparing images.
+A reference screenshot is taken the first time the test runs, and subsequent runs will compare a new screenshot against the reference, at the pixel level.
+
+Here is an [introduction to visual testing by Cypress](https://docs.cypress.io/plugins/directory#visual-testing).
+
+In some cases, we are using visual testing.  
+We are using [Cypress Image Snapshot](https://github.com/jaredpalmer/cypress-image-snapshot)
+
+Identified cases are so far:
+
+- testing images created by OpenRefine backend (scatterplots for example)
+
+Reference screenshots (Called snapshots), are stored in /cypress/snapshots.
+And a snapshot can be taken for the whole page, or just a single part of the page.
+
+#### When a visual test fails
+
+First, Cypress will display the following error message:
+
+![Diff image when a visual test fails](/img/visual-test-cypress-failure.png)
+
+Then, a diff image will be created in /cypress/snapshots, this directory is ignored by Git.  
+The diff images shows the reference image on the left, the image that was taken during the test run on the right, and the diff in the middle.
+
+![Diff image when a visual test fails](/img/failed-visual-test.png)
+
 ## CI/CD
 
 In CI/CD, tests are run headless, with the following command-line

main/tests/cypress/.gitignore

@@ -4,6 +4,7 @@ node_modules
 cypress/videos
 cypress/screenshots
 cypress/downloads
+cypress/snapshots_diffs
 npm-debug.log
 cypress.env.json
 out

main/tests/cypress/cypress/integration/project/grid/column/facet/scatterplot-facet.spec.js

@@ -0,0 +1,167 @@
+// Common configuration for scatterplot snapshots
+// 5% is required, there are some differences between a local run and the images on ubuntu (github actions)
+const matchImageSnapshotOptions = {
+  failureThreshold: 0.05,
+  failureThresholdType: 'percent',
+};
+
+/**
+ * Those tests are generic test to ensure the general behavior of the various facets components
+ * It's using "text facet" as it is the most simple facet
+ */
+describe(__filename, function () {
+  it('Test and verify the matrix against a snapshot (3 integer columns)', function () {
+    cy.loadAndVisitProject('food.small', 'food-small');
+    cy.castColumnTo('Water', 'number');
+    cy.castColumnTo('Energ_Kcal', 'number');
+    cy.castColumnTo('Protein', 'number');
+    cy.columnActionClick('Protein', ['Facet', 'Scatterplot facet']);
+    cy.get('.scatterplot-matrix-table').matchImageSnapshot(
+      'scatterplot-default',
+      matchImageSnapshotOptions
+    );
+  });
+
+  it('Verify the scatterplot matrix order of elements', function () {
+    cy.loadAndVisitProject('food.small', 'food-small');
+    cy.castColumnTo('Water', 'number');
+    cy.castColumnTo('Energ_Kcal', 'number');
+    cy.castColumnTo('Protein', 'number');
+    cy.columnActionClick('Protein', ['Facet', 'Scatterplot facet']);
+    cy.get('.scatterplot-matrix-table').within(() => {
+      // Check row headers
+      cy.get('tr:first-child .column_header').should('to.contain', 'Water');
+      cy.get('tr:nth-child(2) .column_header').should(
+        'to.contain',
+        'Energ_Kcal'
+      );
+      cy.get('tr:nth-child(3) .column_header').should('to.contain', 'Protein');
+      // check first row
+      cy.get('tr:first-child td:nth-child(2) a')
+        .invoke('attr', 'title')
+        .should('eq', 'Water (x) vs. Energ_Kcal (y)');
+      cy.get('tr:first-child td:nth-child(3) a')
+        .invoke('attr', 'title')
+        .should('eq', 'Water (x) vs. Protein (y)');
+      // check second row
+      cy.get('tr:nth-child(2) td:nth-child(2) a')
+        .invoke('attr', 'title')
+        .should('eq', 'Energ_Kcal (x) vs. Protein (y)');
+    });
+  });
+
+  it('Test the rendering options (lin, log, dot sizes) (visual testing)', function () {
+    cy.loadAndVisitProject('food.small', 'food-small');
+    cy.castColumnTo('Water', 'number');
+    cy.castColumnTo('Energ_Kcal', 'number');
+    cy.castColumnTo('Protein', 'number');
+    cy.columnActionClick('Protein', ['Facet', 'Scatterplot facet']);
+
+    // test linear rendering
+    cy.get('.scatterplot-selectors label').contains('lin').click();
+    cy.get('.scatterplot-matrix-table').matchImageSnapshot(
+      'scatterplot-matrix-lin',
+      matchImageSnapshotOptions
+    );
+    // test log rendering
+    cy.get('.scatterplot-selectors label').contains('log').click();
+    cy.get('.scatterplot-matrix-table').matchImageSnapshot(
+      'scatterplot-matrix-log',
+      matchImageSnapshotOptions
+    );
+
+    // test the small dots rendering
+    cy.get('label[title="Small Dot Size"]').click();
+    cy.get('.scatterplot-matrix-table').matchImageSnapshot(
+      'scatterplot-matrix-small-dot',
+      matchImageSnapshotOptions
+    );
+
+    // test the regular dots rendering
+    cy.get('label[title="Regular Dot Size"]').click();
+    cy.get('.scatterplot-matrix-table').matchImageSnapshot(
+      'scatterplot-matrix-regulat-dot',
+      matchImageSnapshotOptions
+    );
+
+    // test the big dots rendering
+    cy.get('label[title="Big Dot Size"]').click();
+    cy.get('.scatterplot-matrix-table').matchImageSnapshot(
+      'scatterplot-matrix-big-dot',
+      matchImageSnapshotOptions
+    );
+  });
+
+  it('Test facet created from the scatterplot matrix', function () {
+    cy.loadAndVisitProject('food.small', 'food-small');
+    cy.castColumnTo('Water', 'number');
+    cy.castColumnTo('Energ_Kcal', 'number');
+    cy.castColumnTo('Protein', 'number');
+    cy.columnActionClick('Protein', ['Facet', 'Scatterplot facet']);
+    // test against the linear screenshot
+    cy.get(
+      '.scatterplot-matrix-table a[title="Water (x) vs. Protein (y)"]'
+    ).click();
+    // test the facet
+    cy.getFacetContainer('Water (x) vs. Protein (y)').should('to.exist');
+    // verify that all the buttons to change the scatterplot look&feel are there + export button
+    cy.getFacetContainer('Water (x) vs. Protein (y)').within(() => {
+      cy.get('label').contains('lin').should('to.exist');
+      cy.get('label').contains('log').should('to.exist');
+      cy.get('label[title="Rotated 45° Counter-Clockwise"]').should('to.exist');
+      cy.get('label[title="No rotation"]').should('to.exist');
+      cy.get('label[title="Rotated 45° Clockwise"]').should('to.exist');
+      cy.get('label[title="Small Dot Size"]').should('to.exist');
+      cy.get('label[title="Regular Dot Size"]').should('to.exist');
+      cy.get('label[title="Big Dot Size"]').should('to.exist');
+      cy.get('a').contains('export plot').should('to.exist');
+    });
+  });
+
+  // it('Test image rendering inside the facet (visual testing)', function () {
+  //   cy.loadAndVisitProject('food.small', 'food-small');
+  //   cy.castColumnTo('Water', 'number');
+  //   cy.castColumnTo('Energ_Kcal', 'number');
+  //   cy.castColumnTo('Protein', 'number');
+  //   cy.columnActionClick('Protein', ['Facet', 'Scatterplot facet']);
+  //   cy.get(
+  //     '.scatterplot-matrix-table a[title="Water (x) vs. Protein (y)"]'
+  //   ).click();
+
+  //   // // verify that all the buttons to change the scatterplot look&feel are there + export button
+  //   // // cy.getFacetContainer('Water (x) vs. Protein (y)').within(() => {
+  //   // // test linear rendering
+  //   // cy.get('#left-panel .scatterplot-selectors label').contains('lin').click();
+  //   // cy.get('#left-panel .facet-scatterplot-plot-container').matchImageSnapshot(
+  //   //   'scatterplot-facet-lin',
+  //   //   matchImageSnapshotOptions
+  //   // );
+  //   // test log rendering
+  //   cy.get('#left-panel .scatterplot-selectors label').contains('log').click();
+  //   cy.get('#left-panel .facet-scatterplot-plot-container').matchImageSnapshot(
+  //     'scatterplot-facet-log',
+  //     matchImageSnapshotOptions
+  //   );
+
+  //   // test the small dots rendering
+  //   cy.get('#left-panel label[title="Small Dot Size"]').click();
+  //   cy.get('#left-panel .facet-scatterplot-plot-container').matchImageSnapshot(
+  //     'scatterplot-facet-small-dot',
+  //     matchImageSnapshotOptions
+  //   );
+
+  //   // test the regular dots rendering
+  //   cy.get('#left-panel label[title="Regular Dot Size"]').click();
+  //   cy.get('#left-panel .facet-scatterplot-plot-container').matchImageSnapshot(
+  //     'scatterplot-facet-regulat-dot',
+  //     matchImageSnapshotOptions
+  //   );
+
+  //   // test the big dots rendering
+  //   cy.get('#left-panel label[title="Big Dot Size"]').click();
+  //   cy.get('#left-panel .facet-scatterplot-plot-container').matchImageSnapshot(
+  //     'scatterplot-facet-big-dot',
+  //     matchImageSnapshotOptions
+  //   );
+  // });
+});

main/tests/cypress/cypress/plugins/index.js

@@ -14,9 +14,14 @@
 /**
  * @type {Cypress.PluginConfig}
  */
+
+const {
+  addMatchImageSnapshotPlugin,
+} = require('cypress-image-snapshot/plugin');
+
 module.exports = (on, config) => {
   // `on` is used to hook into various events Cypress emits
   // `config` is the resolved Cypress config
-
+  addMatchImageSnapshotPlugin(on, config);
   return config;
 };

main/tests/cypress/cypress/support/commands.js

@@ -11,6 +11,10 @@
 import 'cypress-file-upload';
 import 'cypress-wait-until';
 
+import { addMatchImageSnapshotCommand } from 'cypress-image-snapshot/command';
+
+addMatchImageSnapshotCommand({ customDiffDir: 'cypress/snapshots_diffs' });
+
 /**
  * Return the .facets-container for a given facet name
  */
@@ -104,6 +108,7 @@ Cypress.Commands.add('doCreateProjectThroughUserInterface', () => {
  * Cast a whole column to the given type, using Edit Cell / Common transform / To {type}
  */
 Cypress.Commands.add('castColumnTo', (selector, target) => {
+  cy.get('body[ajax_in_progress="false"]');
   cy.get(
     '.data-table th:contains("' + selector + '") .column-header-menu'
   ).click();

main/tests/cypress/package.json

@@ -12,6 +12,7 @@
     },
     "dependencies": {
         "cypress": "6.8.0",
+        "cypress-image-snapshot": "^4.0.1",
         "cypress-file-upload": "^5.0.3",
         "cypress-wait-until": "^1.7.1",
         "dotenv": "^8.2.0",

main/tests/cypress/yarn.lock

@@ -154,6 +154,13 @@ ansi-escapes@^3.0.0:
   resolved "https://registry.yarnpkg.com/ansi-escapes/-/ansi-escapes-3.2.0.tgz"
   integrity sha512-cBhpre4ma+U0T1oM5fXg7Dy1Jw7zzwv7lt/GoCpr+hDQJoYnKVPLL4dCvSEFMmQurOQvSrwT7SL/DAlhBI97RQ==
 
+ansi-escapes@^4.1.0:
+  version "4.3.1"
+  resolved "https://registry.yarnpkg.com/ansi-escapes/-/ansi-escapes-4.3.1.tgz#a5c47cc43181f1f38ffd7076837700d395522a61"
+  integrity sha512-JWF7ocqNrp8u9oqpgV+wH5ftbt+cfvv+PTjOvKLT3AdYly/LmORARfEVT1iyjwN+4MqE5UmVKoAdIBqeoCHgLA==
+  dependencies:
+    type-fest "^0.11.0"
+
 ansi-regex@^2.0.0:
   version "2.1.1"
   resolved "https://registry.yarnpkg.com/ansi-regex/-/ansi-regex-2.1.1.tgz"
@@ -201,6 +208,13 @@ any-observable@^0.3.0:
   resolved "https://registry.yarnpkg.com/any-observable/-/any-observable-0.3.0.tgz"
   integrity sha512-/FQM1EDkTsf63Ub2C6O7GuYFDsSXUwsaZDurV0np41ocwq0jthUAYCmhBX9f+KwlaCgIuWyr/4WlUQUBfKfZog==
 
+app-path@^3.2.0:
+  version "3.2.0"
+  resolved "https://registry.yarnpkg.com/app-path/-/app-path-3.2.0.tgz#06d426e0c988885264e0aa0a766dfa2723491633"
+  integrity sha512-PQPaKXi64FZuofJkrtaO3I5RZESm9Yjv7tkeJaDz4EZMeBBfGtr5MyQ3m5AC7F0HVrISBLatPxAAAgvbe418fQ==
+  dependencies:
+    execa "^1.0.0"
+
 arch@^2.1.2:
   version "2.1.2"
   resolved "https://registry.yarnpkg.com/arch/-/arch-2.1.2.tgz"
@@ -260,6 +274,11 @@ balanced-match@^1.0.0:
   resolved "https://registry.yarnpkg.com/balanced-match/-/balanced-match-1.0.0.tgz"
   integrity sha1-ibTRmasr7kneFk6gK4nORi1xt2c=
 
+base64-js@^1.2.3:
+  version "1.5.1"
+  resolved "https://registry.yarnpkg.com/base64-js/-/base64-js-1.5.1.tgz#1b1b440160a5bf7ad40b650f095963481903930a"
+  integrity sha512-AKpaYlHn8t4SVbOHCy+b5+KKgvR4vrsD8vbvrbiQJps7fKDTkjkDry6ji0rUJjC0kzbNePLwzxq8iypo41qeWA==
+
 bcrypt-pbkdf@^1.0.0:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/bcrypt-pbkdf/-/bcrypt-pbkdf-1.0.2.tgz"
@@ -458,6 +477,17 @@ core-util-is@1.0.2, core-util-is@~1.0.0:
   resolved "https://registry.yarnpkg.com/core-util-is/-/core-util-is-1.0.2.tgz"
   integrity sha1-tf1UIgqivFq1eqtxQMlAdUUDwac=
 
+cross-spawn@^6.0.0:
+  version "6.0.5"
+  resolved "https://registry.yarnpkg.com/cross-spawn/-/cross-spawn-6.0.5.tgz#4a5ec7c64dfae22c3a14124dbacdee846d80cbc4"
+  integrity sha512-eTVLrBSt7fjbDygz805pMnstIs2VTBNkRm0qxZd+M7A5XDdxVRWO5MxGBXZhjY4cqLYLdtrGqRf8mBPmzwSpWQ==
+  dependencies:
+    nice-try "^1.0.4"
+    path-key "^2.0.1"
+    semver "^5.5.0"
+    shebang-command "^1.2.0"
+    which "^1.2.9"
+
 cross-spawn@^7.0.0, cross-spawn@^7.0.2:
   version "7.0.3"
   resolved "https://registry.yarnpkg.com/cross-spawn/-/cross-spawn-7.0.3.tgz"
@@ -474,6 +504,18 @@ cypress-file-upload@^5.0.3:
   dependencies:
     mime "^2.5.0"
 
+cypress-image-snapshot@^4.0.1:
+  version "4.0.1"
+  resolved "https://registry.yarnpkg.com/cypress-image-snapshot/-/cypress-image-snapshot-4.0.1.tgz#59084e713a8d03500c8e053ad7a76f3f18609648"
+  integrity sha512-PBpnhX/XItlx3/DAk5ozsXQHUi72exybBNH5Mpqj1DVmjq+S5Jd9WE5CRa4q5q0zuMZb2V2VpXHth6MjFpgj9Q==
+  dependencies:
+    chalk "^2.4.1"
+    fs-extra "^7.0.1"
+    glob "^7.1.3"
+    jest-image-snapshot "4.2.0"
+    pkg-dir "^3.0.0"
+    term-img "^4.0.0"
+
 cypress-wait-until@^1.7.1:
   version "1.7.1"
   resolved "https://registry.yarnpkg.com/cypress-wait-until/-/cypress-wait-until-1.7.1.tgz"
@@ -765,6 +807,19 @@ eventemitter2@^6.4.2:
   resolved "https://registry.yarnpkg.com/eventemitter2/-/eventemitter2-6.4.3.tgz"
   integrity sha512-t0A2msp6BzOf+QAcI6z9XMktLj52OjGQg+8SJH6v5+3uxNpWYRR3wQmfA+6xtMU9kOC59qk9licus5dYcrYkMQ==
 
+execa@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/execa/-/execa-1.0.0.tgz#c6236a5bb4df6d6f15e88e7f017798216749ddd8"
+  integrity sha512-adbxcyWV46qiHyvSp50TKt05tB4tK3HcmF7/nxfAdhnox83seTDbwnaqKO4sXRy7roHAIFqJP/Rw/AuEbX61LA==
+  dependencies:
+    cross-spawn "^6.0.0"
+    get-stream "^4.0.0"
+    is-stream "^1.1.0"
+    npm-run-path "^2.0.0"
+    p-finally "^1.0.0"
+    signal-exit "^3.0.0"
+    strip-eof "^1.0.0"
+
 execa@^4.0.2:
   version "4.0.3"
   resolved "https://registry.yarnpkg.com/execa/-/execa-4.0.3.tgz"
@@ -861,6 +916,13 @@ file-entry-cache@^6.0.1:
   dependencies:
     flat-cache "^3.0.4"
 
+find-up@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/find-up/-/find-up-3.0.0.tgz#49169f1d7993430646da61ecc5ae355c21c97b73"
+  integrity sha512-1yD6RmLI1XBfxugvORwlck6f75tYL+iR0jqwsOrOxMZyGYqUuDhJ0l4AXdO1iX/FTs9cBAMEk1gWSEx1kSbylg==
+  dependencies:
+    locate-path "^3.0.0"
+
 flat-cache@^3.0.4:
   version "3.0.4"
   resolved "https://registry.yarnpkg.com/flat-cache/-/flat-cache-3.0.4.tgz"
@@ -888,6 +950,15 @@ form-data@~2.3.2:
     combined-stream "^1.0.6"
     mime-types "^2.1.12"
 
+fs-extra@^7.0.1:
+  version "7.0.1"
+  resolved "https://registry.yarnpkg.com/fs-extra/-/fs-extra-7.0.1.tgz#4f189c44aa123b895f722804f55ea23eadc348e9"
+  integrity sha512-YJDaCJZEnBmcbw13fvdAM9AwNOJwOzrE4pqMqBq5nFiEqXUqHwlK4B+3pUw6JNvfSPtX05xFHtYy/1ni01eGCw==
+  dependencies:
+    graceful-fs "^4.1.2"
+    jsonfile "^4.0.0"
+    universalify "^0.1.0"
+
 fs-extra@^9.0.1, fs-extra@^9.1.0:
   version "9.1.0"
   resolved "https://registry.yarnpkg.com/fs-extra/-/fs-extra-9.1.0.tgz"
@@ -908,6 +979,18 @@ functional-red-black-tree@^1.0.1:
   resolved "https://registry.yarnpkg.com/functional-red-black-tree/-/functional-red-black-tree-1.0.1.tgz"
   integrity sha1-GwqzvVU7Kg1jmdKcDj6gslIHgyc=
 
+get-stdin@^5.0.1:
+  version "5.0.1"
+  resolved "https://registry.yarnpkg.com/get-stdin/-/get-stdin-5.0.1.tgz#122e161591e21ff4c52530305693f20e6393a398"
+  integrity sha1-Ei4WFZHiH/TFJTAwVpPyDmOTo5g=
+
+get-stream@^4.0.0:
+  version "4.1.0"
+  resolved "https://registry.yarnpkg.com/get-stream/-/get-stream-4.1.0.tgz#c1b255575f3dc21d59bfc79cd3d2b46b1c3a54b5"
+  integrity sha512-GMat4EJ5161kIy2HevLlr4luNjBgvmj413KaQA7jt4V8B4RDsfpHk7WQ9GVqfYyyx8OS/L66Kox+rJRNklLK7w==
+  dependencies:
+    pump "^3.0.0"
+
 get-stream@^5.0.0:
   version "5.2.0"
   resolved "https://registry.yarnpkg.com/get-stream/-/get-stream-5.2.0.tgz"
@@ -974,6 +1057,16 @@ globals@^13.6.0:
   dependencies:
     type-fest "^0.20.2"
 
+glur@^1.1.2:
+  version "1.1.2"
+  resolved "https://registry.yarnpkg.com/glur/-/glur-1.1.2.tgz#f20ea36db103bfc292343921f1f91e83c3467689"
+  integrity sha1-8g6jbbEDv8KSNDkh8fkeg8NGdok=
+
+graceful-fs@^4.1.2:
+  version "4.2.6"
+  resolved "https://registry.yarnpkg.com/graceful-fs/-/graceful-fs-4.2.6.tgz#ff040b2b0853b23c3d31027523706f1885d76bee"
+  integrity sha512-nTnJ528pbqxYanhpDYsi4Rd8MAeaBA67+RZ10CM1m3bTAVFEDcd5AuA4a6W5YkGZ1iNXHzZz8T6TBKLeBuNriQ==
+
 graceful-fs@^4.1.6, graceful-fs@^4.1.9, graceful-fs@^4.2.0:
   version "4.2.4"
   resolved "https://registry.yarnpkg.com/graceful-fs/-/graceful-fs-4.2.4.tgz"
@@ -1155,6 +1248,29 @@ isstream@~0.1.2:
   resolved "https://registry.yarnpkg.com/isstream/-/isstream-0.1.2.tgz"
   integrity sha1-R+Y/evVa+m+S4VAOaQ64uFKcCZo=
 
+iterm2-version@^4.1.0:
+  version "4.2.0"
+  resolved "https://registry.yarnpkg.com/iterm2-version/-/iterm2-version-4.2.0.tgz#b78069f747f34a772bc7dc17bda5bd9ed5e09633"
+  integrity sha512-IoiNVk4SMPu6uTcK+1nA5QaHNok2BMDLjSl5UomrOixe5g4GkylhPwuiGdw00ysSCrXAKNMfFTu+u/Lk5f6OLQ==
+  dependencies:
+    app-path "^3.2.0"
+    plist "^3.0.1"
+
+jest-image-snapshot@4.2.0:
+  version "4.2.0"
+  resolved "https://registry.yarnpkg.com/jest-image-snapshot/-/jest-image-snapshot-4.2.0.tgz#559d7ade69e9918517269cef184261c80029a69e"
+  integrity sha512-6aAqv2wtfOgxiJeBayBCqHo1zX+A12SUNNzo7rIxiXh6W6xYVu8QyHWkada8HeRi+QUTHddp0O0Xa6kmQr+xbQ==
+  dependencies:
+    chalk "^1.1.3"
+    get-stdin "^5.0.1"
+    glur "^1.1.2"
+    lodash "^4.17.4"
+    mkdirp "^0.5.1"
+    pixelmatch "^5.1.0"
+    pngjs "^3.4.0"
+    rimraf "^2.6.2"
+    ssim.js "^3.1.1"
+
 js-tokens@^4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/js-tokens/-/js-tokens-4.0.0.tgz"
@@ -1225,6 +1341,13 @@ json-stringify-safe@~5.0.1:
   resolved "https://registry.yarnpkg.com/json-stringify-safe/-/json-stringify-safe-5.0.1.tgz"
   integrity sha1-Epai1Y/UXxmg9s4B1lcB4sc1tus=
 
+jsonfile@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/jsonfile/-/jsonfile-4.0.0.tgz#8771aae0799b64076b76640fca058f9c10e33ecb"
+  integrity sha1-h3Gq4HmbZAdrdmQPygWPnBDjPss=
+  optionalDependencies:
+    graceful-fs "^4.1.6"
+
 jsonfile@^6.0.1:
   version "6.0.1"
   resolved "https://registry.yarnpkg.com/jsonfile/-/jsonfile-6.0.1.tgz"
@@ -1315,12 +1438,20 @@ listr@^0.14.3:
     p-map "^2.0.0"
     rxjs "^6.3.3"
 
+locate-path@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/locate-path/-/locate-path-3.0.0.tgz#dbec3b3ab759758071b58fe59fc41871af21400e"
+  integrity sha512-7AO748wWnIhNqAuaty2ZWHkQHRSNfPVIsPIfwEOWO22AmaoVrWavlOcMR5nzTLNYvp36X220/maaRsrec1G65A==
+  dependencies:
+    p-locate "^3.0.0"
+    path-exists "^3.0.0"
+
 lodash.once@^4.1.1:
   version "4.1.1"
   resolved "https://registry.yarnpkg.com/lodash.once/-/lodash.once-4.1.1.tgz"
   integrity sha1-DdOXEhPHxW34gJd9UEyI+0cal6w=
 
-lodash@^4.17.14, lodash@^4.17.19, lodash@^4.17.20, lodash@^4.17.21:
+lodash@^4.17.14, lodash@^4.17.19, lodash@^4.17.20, lodash@^4.17.21, lodash@^4.17.4:
   version "4.17.21"
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.21.tgz#679591c564c3bffaae8454cf0b3df370c3d6911c"
   integrity sha512-v2kDEe57lecTulaDIuNTPy3Ry4gLGJ6Z1O3vE1krgXZNrsQ+LFTGHVxVjcXPs17LhbZVGedAJv8XZ1tvj5FvSg==
@@ -1425,7 +1556,7 @@ minimist@^1.2.5:
   resolved "https://registry.yarnpkg.com/minimist/-/minimist-1.2.5.tgz"
   integrity sha512-FM9nNUYrRBAELZQT3xeZQ7fmMOBg6nWNmJKTcgsJeaLstP/UODVpGsr5OhXhhXg6f+qtJ8uiZ+PUxkDWcgIXLw==
 
-mkdirp@^0.5.4:
+mkdirp@^0.5.1, mkdirp@^0.5.4:
   version "0.5.5"
   resolved "https://registry.yarnpkg.com/mkdirp/-/mkdirp-0.5.5.tgz"
   integrity sha512-NKmAlESf6jMGym1++R0Ra7wvhV+wFW63FaSOFPwRahvea0gMUcGUhVeAg/0BC0wiv9ih5NYPB1Wn1UEI1/L+xQ==
@@ -1457,6 +1588,18 @@ natural-compare@^1.4.0:
   resolved "https://registry.yarnpkg.com/natural-compare/-/natural-compare-1.4.0.tgz"
   integrity sha1-Sr6/7tdUHywnrPspvbvRXI1bpPc=
 
+nice-try@^1.0.4:
+  version "1.0.5"
+  resolved "https://registry.yarnpkg.com/nice-try/-/nice-try-1.0.5.tgz#a3378a7696ce7d223e88fc9b764bd7ef1089e366"
+  integrity sha512-1nh45deeb5olNY7eX82BkPO7SSxR5SSYJiPTrTdFUVYwAl8CKMA5N9PjTYkHiRjisVcxcQ1HXdLhx2qxxJzLNQ==
+
+npm-run-path@^2.0.0:
+  version "2.0.2"
+  resolved "https://registry.yarnpkg.com/npm-run-path/-/npm-run-path-2.0.2.tgz#35a9232dfa35d7067b4cb2ddf2357b1871536c5f"
+  integrity sha1-NakjLfo11wZ7TLLd8jV7GHFTbF8=
+  dependencies:
+    path-key "^2.0.0"
+
 npm-run-path@^4.0.0:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/npm-run-path/-/npm-run-path-4.0.1.tgz"
@@ -1522,11 +1665,35 @@ ospath@^1.2.2:
   resolved "https://registry.yarnpkg.com/ospath/-/ospath-1.2.2.tgz"
   integrity sha1-EnZjl3Sj+O8lcvf+QoDg6kVQwHs=
 
+p-finally@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/p-finally/-/p-finally-1.0.0.tgz#3fbcfb15b899a44123b34b6dcc18b724336a2cae"
+  integrity sha1-P7z7FbiZpEEjs0ttzBi3JDNqLK4=
+
+p-limit@^2.0.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/p-limit/-/p-limit-2.3.0.tgz#3dd33c647a214fdfffd835933eb086da0dc21db1"
+  integrity sha512-//88mFWSJx8lxCzwdAABTJL2MyWB12+eIY7MDL2SqLmAkeKU9qxRvWuSyTjm3FUmpBEMuFfckAIqEaVGUDxb6w==
+  dependencies:
+    p-try "^2.0.0"
+
+p-locate@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/p-locate/-/p-locate-3.0.0.tgz#322d69a05c0264b25997d9f40cd8a891ab0064a4"
+  integrity sha512-x+12w/To+4GFfgJhBEpiDcLozRJGegY+Ei7/z0tSLkMmxGZNybVMSfWj9aJn8Z5Fc7dBUNJOOVgPv2H7IwulSQ==
+  dependencies:
+    p-limit "^2.0.0"
+
 p-map@^2.0.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/p-map/-/p-map-2.1.0.tgz"
   integrity sha512-y3b8Kpd8OAN444hxfBbFfj1FY/RjtTd8tzYwhUqNYXx0fXx2iX4maP4Qr6qhIKbQXI02wTLAda4fYUbDagTUFw==
 
+p-try@^2.0.0:
+  version "2.2.0"
+  resolved "https://registry.yarnpkg.com/p-try/-/p-try-2.2.0.tgz#cb2868540e313d61de58fafbe35ce9004d5540e6"
+  integrity sha512-R4nPAVTAU0B9D35/Gk3uJf/7XYbQcyohSKdvAxIRSNghFl4e71hVoGnBNQz9cWaXxO2I10KTC+3jMdvvoKw6dQ==
+
 parent-module@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/parent-module/-/parent-module-1.0.1.tgz"
@@ -1534,11 +1701,21 @@ parent-module@^1.0.0:
   dependencies:
     callsites "^3.0.0"
 
+path-exists@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/path-exists/-/path-exists-3.0.0.tgz#ce0ebeaa5f78cb18925ea7d810d7b59b010fd515"
+  integrity sha1-zg6+ql94yxiSXqfYENe1mwEP1RU=
+
 path-is-absolute@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/path-is-absolute/-/path-is-absolute-1.0.1.tgz"
   integrity sha1-F0uSaHNVNP+8es5r9TpanhtcX18=
 
+path-key@^2.0.0, path-key@^2.0.1:
+  version "2.0.1"
+  resolved "https://registry.yarnpkg.com/path-key/-/path-key-2.0.1.tgz#411cadb574c5a140d3a4b1910d40d80cc9f40b40"
+  integrity sha1-QRyttXTFoUDTpLGRDUDYDMn0C0A=
+
 path-key@^3.0.0, path-key@^3.1.0:
   version "3.1.1"
   resolved "https://registry.yarnpkg.com/path-key/-/path-key-3.1.1.tgz"
@@ -1559,6 +1736,39 @@ pify@^2.2.0:
   resolved "https://registry.yarnpkg.com/pify/-/pify-2.3.0.tgz"
   integrity sha1-7RQaasBDqEnqWISY59yosVMw6Qw=
 
+pixelmatch@^5.1.0:
+  version "5.2.1"
+  resolved "https://registry.yarnpkg.com/pixelmatch/-/pixelmatch-5.2.1.tgz#9e4e4f4aa59648208a31310306a5bed5522b0d65"
+  integrity sha512-WjcAdYSnKrrdDdqTcVEY7aB7UhhwjYQKYhHiBXdJef0MOaQeYpUdQ+iVyBLa5YBKS8MPVPPMX7rpOByISLpeEQ==
+  dependencies:
+    pngjs "^4.0.1"
+
+pkg-dir@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/pkg-dir/-/pkg-dir-3.0.0.tgz#2749020f239ed990881b1f71210d51eb6523bea3"
+  integrity sha512-/E57AYkoeQ25qkxMj5PBOVgF8Kiu/h7cYS30Z5+R7WaiCCBfLq58ZI/dSeaEKb9WVJV5n/03QwrN3IeWIFllvw==
+  dependencies:
+    find-up "^3.0.0"
+
+plist@^3.0.1:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/plist/-/plist-3.0.1.tgz#a9b931d17c304e8912ef0ba3bdd6182baf2e1f8c"
+  integrity sha512-GpgvHHocGRyQm74b6FWEZZVRroHKE1I0/BTjAmySaohK+cUn+hZpbqXkc3KWgW3gQYkqcQej35FohcT0FRlkRQ==
+  dependencies:
+    base64-js "^1.2.3"
+    xmlbuilder "^9.0.7"
+    xmldom "0.1.x"
+
+pngjs@^3.4.0:
+  version "3.4.0"
+  resolved "https://registry.yarnpkg.com/pngjs/-/pngjs-3.4.0.tgz#99ca7d725965fb655814eaf65f38f12bbdbf555f"
+  integrity sha512-NCrCHhWmnQklfH4MtJMRjZ2a8c80qXeMlQMv2uVp9ISJMTt562SbGd6n2oq0PaPgKm7Z6pL9E2UlLIhC+SHL3w==
+
+pngjs@^4.0.1:
+  version "4.0.1"
+  resolved "https://registry.yarnpkg.com/pngjs/-/pngjs-4.0.1.tgz#f803869bb2fc1bfe1bf99aa4ec21c108117cfdbe"
+  integrity sha512-rf5+2/ioHeQxR6IxuYNYGFytUyG3lma/WW1nsmjeHlWwtb2aByla6dkVc8pmJ9nplzkTA0q2xx7mMWrOTqT4Gg==
+
 prelude-ls@^1.2.1:
   version "1.2.1"
   resolved "https://registry.yarnpkg.com/prelude-ls/-/prelude-ls-1.2.1.tgz"
@@ -1680,6 +1890,13 @@ restore-cursor@^2.0.0:
     onetime "^2.0.0"
     signal-exit "^3.0.2"
 
+rimraf@^2.6.2:
+  version "2.7.1"
+  resolved "https://registry.yarnpkg.com/rimraf/-/rimraf-2.7.1.tgz#35797f13a7fdadc566142c29d4f07ccad483e3ec"
+  integrity sha512-uWjbaKIK3T1OSVptzX7Nl6PvQ3qAGtKEtVRjRuazjfL3Bx5eI409VZSqgND+4UNnmzLVdPj9FqFJNPqBZFve4w==
+  dependencies:
+    glob "^7.1.3"
+
 rimraf@^3.0.0, rimraf@^3.0.2:
   version "3.0.2"
   resolved "https://registry.yarnpkg.com/rimraf/-/rimraf-3.0.2.tgz"
@@ -1709,6 +1926,11 @@ safer-buffer@^2.0.2, safer-buffer@^2.1.0, safer-buffer@~2.1.0:
   resolved "https://registry.yarnpkg.com/safer-buffer/-/safer-buffer-2.1.2.tgz"
   integrity sha512-YZo3K82SD7Riyi0E1EQPojLz7kpepnSQI9IyPbHHg1XXXevb5dJI7tpyN2ADxGcQbHG7vcyRHk0cbwqcQriUtg==
 
+semver@^5.5.0:
+  version "5.7.1"
+  resolved "https://registry.yarnpkg.com/semver/-/semver-5.7.1.tgz#a954f931aeba508d307bbf069eff0c01c96116f7"
+  integrity sha512-sauaDf/PZdVgrLTNYHRtpXa1iRiKcaebiKQ1BJdpQlWH2lCvexQdX55snPFyK7QzpudqbCI0qXFfOasHdyNDGQ==
+
 semver@^7.2.1:
   version "7.3.4"
   resolved "https://registry.yarnpkg.com/semver/-/semver-7.3.4.tgz"
@@ -1716,6 +1938,13 @@ semver@^7.2.1:
   dependencies:
     lru-cache "^6.0.0"
 
+shebang-command@^1.2.0:
+  version "1.2.0"
+  resolved "https://registry.yarnpkg.com/shebang-command/-/shebang-command-1.2.0.tgz#44aac65b695b03398968c39f363fee5deafdf1ea"
+  integrity sha1-RKrGW2lbAzmJaMOfNj/uXer98eo=
+  dependencies:
+    shebang-regex "^1.0.0"
+
 shebang-command@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/shebang-command/-/shebang-command-2.0.0.tgz"
@@ -1723,12 +1952,17 @@ shebang-command@^2.0.0:
   dependencies:
     shebang-regex "^3.0.0"
 
+shebang-regex@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/shebang-regex/-/shebang-regex-1.0.0.tgz#da42f49740c0b42db2ca9728571cb190c98efea3"
+  integrity sha1-2kL0l0DAtC2yypcoVxyxkMmO/qM=
+
 shebang-regex@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/shebang-regex/-/shebang-regex-3.0.0.tgz"
   integrity sha512-7++dFhtcx3353uBaq8DDR4NuxBetBzC7ZQOhmTQInHEd6bSrXdiEyzCvG07Z44UYdLShWUyXt5M/yhz8ekcb1A==
 
-signal-exit@^3.0.2:
+signal-exit@^3.0.0, signal-exit@^3.0.2:
   version "3.0.3"
   resolved "https://registry.yarnpkg.com/signal-exit/-/signal-exit-3.0.3.tgz"
   integrity sha512-VUJ49FC8U1OxwZLxIbTTrDvLnf/6TDgxZcK8wxR8zs13xpx7xbG60ndBlhNrFi2EMuFRoeDoJO7wthSLq42EjA==
@@ -1767,6 +2001,11 @@ sshpk@^1.7.0:
     safer-buffer "^2.0.2"
     tweetnacl "~0.14.0"
 
+ssim.js@^3.1.1:
+  version "3.5.0"
+  resolved "https://registry.yarnpkg.com/ssim.js/-/ssim.js-3.5.0.tgz#d7276b9ee99b57a5ff0db34035f02f35197e62df"
+  integrity sha512-Aj6Jl2z6oDmgYFFbQqK7fght19bXdOxY7Tj03nF+03M9gCBAjeIiO8/PlEGMfKDwYpw4q6iBqVq2YuREorGg/g==
+
 string-width@^1.0.1:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/string-width/-/string-width-1.0.2.tgz"
@@ -1821,6 +2060,11 @@ strip-ansi@^6.0.0:
   dependencies:
     ansi-regex "^5.0.0"
 
+strip-eof@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/strip-eof/-/strip-eof-1.0.0.tgz#bb43ff5598a6eb05d89b59fcd129c983313606bf"
+  integrity sha1-u0P/VZim6wXYm1n80SnJgzE2Br8=
+
 strip-final-newline@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/strip-final-newline/-/strip-final-newline-2.0.0.tgz"
@@ -1870,6 +2114,14 @@ taffydb@2.6.2:
   resolved "https://registry.yarnpkg.com/taffydb/-/taffydb-2.6.2.tgz#7cbcb64b5a141b6a2efc2c5d2c67b4e150b2a268"
   integrity sha1-fLy2S1oUG2ou/CxdLGe04VCyomg=
 
+term-img@^4.0.0:
+  version "4.1.0"
+  resolved "https://registry.yarnpkg.com/term-img/-/term-img-4.1.0.tgz#5b170961f7aa20b2f3b22deb8ad504beb963a8a5"
+  integrity sha512-DFpBhaF5j+2f7kheKFc1ajsAUUDGOaNPpKPtiIMxlbfud6mvfFZuWGnTRpaujUa5J7yl6cIw/h6nyr4mSsENPg==
+  dependencies:
+    ansi-escapes "^4.1.0"
+    iterm2-version "^4.1.0"
+
 text-table@^0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/text-table/-/text-table-0.2.0.tgz"
@@ -1919,6 +2171,11 @@ type-check@^0.4.0, type-check@~0.4.0:
   dependencies:
     prelude-ls "^1.2.1"
 
+type-fest@^0.11.0:
+  version "0.11.0"
+  resolved "https://registry.yarnpkg.com/type-fest/-/type-fest-0.11.0.tgz#97abf0872310fed88a5c466b25681576145e33f1"
+  integrity sha512-OdjXJxnCN1AvyLSzeKIgXTXxV+99ZuXl3Hpo9XpJAv9MBcHrrJOQ5kV7ypXOuQie+AmWG25hLbiKdwYTifzcfQ==
+
 type-fest@^0.20.2:
   version "0.20.2"
   resolved "https://registry.yarnpkg.com/type-fest/-/type-fest-0.20.2.tgz#1bf207f4b28f91583666cb5fbd327887301cd5f4"
@@ -1949,6 +2206,11 @@ uniqid@^5.3.0:
   resolved "https://registry.yarnpkg.com/uniqid/-/uniqid-5.3.0.tgz#4545f8e9c9a5830ef804e512cca6a9331e9761bf"
   integrity sha512-Jq8EzvAT8/CcLu8tzoSiylnzPkNhJJKpnMT964Dj1jI4pG4sKYP9aFVByNTp8KzMvYlW1Um63PCDqtOoujNzrA==
 
+universalify@^0.1.0:
+  version "0.1.2"
+  resolved "https://registry.yarnpkg.com/universalify/-/universalify-0.1.2.tgz#b646f69be3942dabcecc9d6639c80dc105efaa66"
+  integrity sha512-rBJeI5CXAlmy1pV+617WB9J63U6XcazHHF2f2dbJix4XzpUF0RS3Zbj0FGIOCAva5P/d/GBOYaACQ1w+0azUkg==
+
 universalify@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/universalify/-/universalify-1.0.0.tgz"
@@ -2003,6 +2265,13 @@ verror@1.10.0:
     core-util-is "1.0.2"
     extsprintf "^1.2.0"
 
+which@^1.2.9:
+  version "1.3.1"
+  resolved "https://registry.yarnpkg.com/which/-/which-1.3.1.tgz#a45043d54f5805316da8d62f9f50918d3da70b0a"
+  integrity sha512-HxJdYWq1MTIQbJ3nw0cqssHoTNU267KlrDuGZ1WYlxDStUtKUhOaJmh112/TZmHxxUfuJqPXSOm7tDyas0OSIQ==
+  dependencies:
+    isexe "^2.0.0"
+
 which@^2.0.1:
   version "2.0.2"
   resolved "https://registry.yarnpkg.com/which/-/which-2.0.2.tgz"
@@ -2028,11 +2297,21 @@ wrappy@1:
   resolved "https://registry.yarnpkg.com/wrappy/-/wrappy-1.0.2.tgz"
   integrity sha1-tSQ9jz7BqjXxNkYFvA0QNuMKtp8=
 
+xmlbuilder@^9.0.7:
+  version "9.0.7"
+  resolved "https://registry.yarnpkg.com/xmlbuilder/-/xmlbuilder-9.0.7.tgz#132ee63d2ec5565c557e20f4c22df9aca686b10d"
+  integrity sha1-Ey7mPS7FVlxVfiD0wi35rKaGsQ0=
+
 xmlcreate@^2.0.3:
   version "2.0.3"
   resolved "https://registry.yarnpkg.com/xmlcreate/-/xmlcreate-2.0.3.tgz#df9ecd518fd3890ab3548e1b811d040614993497"
   integrity sha512-HgS+X6zAztGa9zIK3Y3LXuJes33Lz9x+YyTxgrkIdabu2vqcGOWwdfCpf1hWLRrd553wd4QCDf6BBO6FfdsRiQ==
 
+xmldom@0.1.x:
+  version "0.1.31"
+  resolved "https://registry.yarnpkg.com/xmldom/-/xmldom-0.1.31.tgz#b76c9a1bd9f0a9737e5a72dc37231cf38375e2ff"
+  integrity sha512-yS2uJflVQs6n+CyjHoaBmVSqIDevTAWrzMmjG1Gc7h1qQ7uVozNhEPJAwZXWyGQ/Gafo3fCwrcaokezLPupVyQ==
+
 yallist@^4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/yallist/-/yallist-4.0.0.tgz"