first commit

node_modules/eslint-plugin-cypress/lib/rules/assertion-before-screenshot.js

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+'use strict'
+
+const assertionCommands = [
+  // assertions
+  'should',
+  'and',
+  'contains',
+
+  // retries until it gets something
+  'get',
+
+  // not an assertion, but unlikely to require waiting for render
+  'scrollIntoView',
+  'scrollTo',
+]
+
+module.exports = {
+  meta: {
+    docs: {
+      description: 'Assert on the page state before taking a screenshot, so the screenshot is consistent',
+      category: 'Possible Errors',
+      recommended: false,
+    },
+    schema: [],
+    messages: {
+      unexpected: 'Make an assertion on the page state before taking a screenshot',
+    },
+  },
+  create (context) {
+    return {
+      CallExpression (node) {
+        if (isCallingCyScreenshot(node) && !isPreviousAnAssertion(node)) {
+          context.report({ node, messageId: 'unexpected' })
+        }
+      },
+    }
+  },
+}
+
+function isRootCypress (node) {
+  while (node.type === 'CallExpression') {
+    if (node.callee.type !== 'MemberExpression') return false
+
+    if (node.callee.object.type === 'Identifier' &&
+        node.callee.object.name === 'cy') {
+      return true
+    }
+
+    node = node.callee.object
+  }
+
+  return false
+}
+
+function getPreviousInChain (node) {
+  return node.type === 'CallExpression' &&
+         node.callee.type === 'MemberExpression' &&
+         node.callee.object.type === 'CallExpression' &&
+         node.callee.object.callee.type === 'MemberExpression' &&
+         node.callee.object.callee.property.type === 'Identifier' &&
+         node.callee.object.callee.property.name
+}
+
+function getCallExpressionCypressCommand (node) {
+  return isRootCypress(node) &&
+         node.callee.property.type === 'Identifier' &&
+         node.callee.property.name
+}
+
+function isCallingCyScreenshot (node) {
+  return getCallExpressionCypressCommand(node) === 'screenshot'
+}
+
+function getPreviousCypressCommand (node) {
+  const previousInChain = getPreviousInChain(node)
+
+  if (previousInChain) {
+    return previousInChain
+  }
+
+  while (node.parent && !node.parent.body) {
+    node = node.parent
+  }
+
+  if (!node.parent || !node.parent.body) return null
+
+  const body = node.parent.body.type === 'BlockStatement' ? node.parent.body.body : node.parent.body
+
+  const index = body.indexOf(node)
+
+  // in the case of a function declaration it won't be found
+  if (index < 0) return null
+
+  if (index === 0) return getPreviousCypressCommand(node.parent)
+
+  const previousStatement = body[index - 1]
+
+  if (previousStatement.type !== 'ExpressionStatement' ||
+      previousStatement.expression.type !== 'CallExpression') {
+    return null
+  }
+
+  return getCallExpressionCypressCommand(previousStatement.expression)
+}
+
+function isPreviousAnAssertion (node) {
+  const previousCypressCommand = getPreviousCypressCommand(node)
+
+  return assertionCommands.indexOf(previousCypressCommand) >= 0
+}