Snapshotting still occurs when numTestsKeptInMemory is 0

[CoryDanielson]

Current behavior:

When running cypress in GUI mode with numTestsKeptInMemory set to 0, snapshotting still occurs even though none of them should be kept in memory. This has a negative impact on performance and memory consumption.

In this screenshot, you can see that numTestsKeptInMemory is 0, but 5 seconds is spent taking snapshots that will not be used.

In this screenshot you can see where the majority of the snapshot execution took place, 3.4s converting rules from large stylesheets into a string, and 0.4s replacing URLs in those strings with absolute paths.

Desired behavior:

When running with numTestsKeptInMemory set to 0, snapshotting should be avoided in the same way that occurs while running in headless mode.

• https://github.com/cypress-io/cypress/blob/develop/packages/driver/src/cypress/log.coffee#L262-L266

Steps to reproduce:

1. Set numTestsKeptInMemory to 0.
2. Run cypress GUI mode.

Versions

Cypress: 3.2.0
Chrome: Chrome 74

[jennifer-shehane]

Hey @CoryDanielson, can you take a look at your resolved configuration and confirm that the numTestsKeptInMemory configuration is being read as set to 0? https://on.cypress.io/configuration#Resolved-Configuration

[CoryDanielson]

@jennifer-shehane I updated the original post with new screenshots.

[CoryDanielson]

I opened up a PR to address this #4123

I extended the if statement to include a check for numTestsKeptInMemory

    snapshot: (name, options = {}) ->
      ## bail early and dont snapshot
      ## if we're in headless mode
      ## TODO: fix this
      if not config("isInteractive") || _.toString(config("numTestsKeptInMemory")) is '0'
        return @

[brian-mann]

I'll take this PR from here and we'll get it out in the next patch release or so.