From f2f7d76d756f31d02c1eb697966ce759e306a55c Mon Sep 17 00:00:00 2001
From: Stuart Long <stuartlo@microsoft.com>
Date: Fri, 26 Apr 2019 13:38:33 -0700
Subject: [PATCH] feat: add support for relative snapshots (#21)

* feat: Add capability for relative snapshot files

* feat: remove path from package

* feat: remove nsp from pre-push since it's deprecated

* feat: use Cypress config instead

* feat: fix build
---
 README.md    | 19 ++++++++++++++++++-
 src/index.js | 48 +++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 61 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index a20d841..df6b088 100644
--- a/README.md
+++ b/README.md
@@ -48,7 +48,7 @@ describe('focused input field', () => {
 })
 ```
 
-The snapshot object can be found in file `snapshots.js`. In the above case it would look something like this
+By default, the snapshot object can be found in file `snapshots.js`. In the above case it would look something like this
 
 ```js
 module.exports = {
@@ -103,6 +103,23 @@ cy.get(...).snapshot({
 })
 ```
 
+### Configuration
+
+This module provides some configuration options:
+
+#### useRelativeSnapshots
+Set to true in order to store your snapshots for each test run next to the inital test caller rather
+than at the base working directory.
+
+**Note:** requires the `readFileMaybe` plugin to be configured see https://on.cypress.io/task#Read-a-file-that-might-not-exist
+
+#### snapshotFileName
+Set to a string to name your snapshot something other than 'snapshots.js'
+
+#### Usage
+Set the configuration options as part of the Cypress config.
+See https://docs.cypress.io/guides/references/configuration.html
+
 ## Debugging
 
 To debug this module run with environment variable `DEBUG=@cypress/snapshot`
diff --git a/src/index.js b/src/index.js
index 4144779..1ad4b70 100644
--- a/src/index.js
+++ b/src/index.js
@@ -6,6 +6,7 @@ const { initStore } = require('snap-shot-store')
 const la = require('lazy-ass')
 const is = require('check-more-types')
 const compare = require('snap-shot-compare')
+const path = require('path')
 
 const {
   serializeDomElement,
@@ -14,6 +15,14 @@ const {
   countSnapshots
 } = require('./utils')
 
+const DEFAULT_CONFIG_OPTIONS = {
+  // using relative snapshots requires a simple
+  // 'readFileMaybe' plugin to be configured
+  // see https://on.cypress.io/task#Read-a-file-that-might-not-exist
+  useRelativeSnapshots: false,
+  snapshotFileName: 'snapshots.js'
+}
+
 /* eslint-disable no-console */
 
 function compareValues ({ expected, value }) {
@@ -27,6 +36,12 @@ function registerCypressSnapshot () {
   la(is.fn(global.after), 'missing global after function')
   la(is.object(global.Cypress), 'missing Cypress object')
 
+  const useRelative = Cypress.config("useRelativeSnapshots")
+  const config = {
+    useRelativeSnapshots: useRelative === undefined ? DEFAULT_CONFIG_OPTIONS.useRelativeSnapshots : useRelative,
+    snapshotFileName: Cypress.config("snapshotFileName") || DEFAULT_CONFIG_OPTIONS.snapshotFileName
+  }
+
   console.log('registering @cypress/snapshot')
 
   let storeSnapshot
@@ -48,7 +63,15 @@ function registerCypressSnapshot () {
     return counters[key]
   }
 
-  const SNAPSHOT_FILENAME = 'snapshots.js'
+  let snapshotFileName = config.snapshotFileName
+  if (config.useRelativeSnapshots) {
+    let relative = Cypress.spec.relative
+    if (Cypress.platform === 'win32') {
+      relative = relative.replace(/\\/g, path.sep)
+    }
+
+    snapshotFileName = path.join(path.dirname(relative), config.snapshotFileName)
+  }
 
   function evaluateLoadedSnapShots (js) {
     la(is.string(js), 'expected JavaScript snapshot source', js)
@@ -59,9 +82,24 @@ function registerCypressSnapshot () {
   }
 
   global.before(function loadSnapshots () {
-    cy
-    .readFile(SNAPSHOT_FILENAME, 'utf-8', { log: false })
-    .then(evaluateLoadedSnapShots)
+    let readFile
+
+    if (config.useRelativeSnapshots) {
+      readFile = cy
+      .task('readFileMaybe', snapshotFileName)
+      .then(function (contents) {
+        if (!contents) {
+          return cy.writeFile(snapshotFileName, '', 'utf-8', { log: false })
+        }
+
+        return contents
+      })
+    } else {
+      readFile = cy
+      .readFile(snapshotFileName, 'utf-8')
+    }
+
+    readFile.then(evaluateLoadedSnapShots)
     // no way to catch an error yet
   })
 
@@ -161,7 +199,7 @@ function registerCypressSnapshot () {
       snapshots.__version = Cypress.version
       const s = JSON.stringify(snapshots, null, 2)
       const str = `module.exports = ${s}\n`
-      cy.writeFile(SNAPSHOT_FILENAME, str, 'utf-8', { log: false })
+      cy.writeFile(snapshotFileName, str, 'utf-8', { log: false })
     }
   })