Closes #464.

Signed-off-by: Martin Afanasjew <martin@afanasjew.de>

Add an extension for accessing Git-related meta data that can be mixed
in into a Pathname object (e.g. `HOMBREW_REPOSITORY` or the path of a
`Tap` instance). The goal here is to eliminate code duplication.

Remove an exact duplicate from further up in the same file. (It was
accidentally added in 8a582f2b.)

Closes #460.

Signed-off-by: Xu Cheng <xucheng@me.com>

Implement:
  * VCSDownloadStrategy#last_commit
    Use last modified file timestamp
  * SubversionDownloadStrategy#last_commit
    Use `svn info --show-item revision`
  * GitDownloadStrategy#last_commit
    Use `git rev-parse HEAD`
  * MercurialDownloadStrategy#last_commit
    Use `hg parent --template {node}`
  * BazaarDownloadStrategy#last_commit
    Use `bazaar revno`
  * FossilDownloadStrategy#last_commit
  Use `fossil info tip`

Closes https://github.com/Homebrew/homebrew-core/issues/2758

Beta versions of XQuartz have address sanitization enabled, which
breaks some software at runtime, including wine.

Closes Homebrew/homebrew-core#2481.

Closes #459.

Signed-off-by: Misty De Meo <mistydemeo@github.com>

Rearrange path constants such that persistent paths (that point into the
Homebrew code base) are in one spot and all other paths (that are being
redirected to a temporary location for the duration of the test run) are
grouped together.

Closes #440.

Signed-off-by: Martin Afanasjew <martin@afanasjew.de>

Truncates each log file to about 1 MB. This avoids upload and
download errors with the gists, and respects GitHub's suggested
size limits.

Prior to the fix, every run of the test suite would leave behind a pair
of empty directories in `$TMPDIR`. (A temporary home directory was
created but only its child `Applications` was wiped when done.)

This reverts commit dba1958b.

This reverts commit 252c701c.

Taps installed prior to running the test suite are not visible to the
test suite as most Homebrew paths are redefined as to not mess up the
local installation.

Since we've moved all formulae to taps it's not necessarily obvious
what the path for the files are otherwise.

All of these taps use Homebrew internal APIs (or will shortly) and we
autoinstall them all from `brew $CMD`. We should adjust our CI to ensure
that we never accidentally break these taps when making changes to core
code so that these taps can rely more on this core code rather than
having to e.g. vendor equivalent code that never changes on our end.

This is a developer-only option I created for testing purposes. It
should not be used by end-users.

Set HOMEBREW_NO_GITHUB_API to allow running all tests (but search's
integration test specifically for now) offline. This can be overridden
with `--online`.

Adjust the wording to be in sync with the changes made in #424.

strategy is an undefined variable

Tweak `Style/NumericLiteralPrefix` cop settings as we're using octal
literals a lot (both in formulae and the package manager) for file
permissions and aren't ready just yet to transition them to the more
beginner-friendly `0o` prefix (instead of the more obscure `0` prefix).

Ensures that the data gets written to disk so curl can see it, avoiding
intermittent JSON parsing errors in gist creation.

Do this to ensure that any symlinks in the Homebrew prefix and/or in
Applications are removed to stop issues with stale symlinks causing
Casks from being installed correctly.

* take requirements into account.
* handle full qualified formula name.
* filter out build time or unused optional deps/requirements.

Closes #424.

Signed-off-by: Xu Cheng <xucheng@me.com>

Also allowing access results for LinkageChecker