Use "diskutil unmount force" to unmount DMGs.

These locations are now all automatically cleaned up after every test.

These are no longer necessary.

(No longer just integration tests.)

This will allow us to have global setup and teardown for tests.

For example, we can automatically clear caches after each test, to avoid
annoying intermittent failures like #1879 and #1886.

This seems to be a remnant of Ruby 1.8.

Similar to 6fc1747e. I hadn't seen any
test failures caused by this, but I noticed it in the process of
trackign that down and it's an accident waiting to happen.

This was responsible for the sporadic failures I encountered in #1878.

Also, report formulae installed on request. This is useful in
differentiating between those formulae that are popular because they
are widely requested and those that are popular because they are widely
depended on.

Which, in turn, provides them for `brew info --json=v1` so other tools
such as e.g. `brew bundle` can make use of this information.

These are used to determine whether or not a formula’s install was
specifically requested by a user and/or pulled in as a dependency.

Instead of `puts`ing when the failure occurs save it until the error
message and print a prose description of what the failure was and the
output from the command. This makes the output from failing tests
significantly easier to read.

Rather than all versioned formulae regardless. Oops.

This would have eliminated the need for Homebrew/homebrew-core#9000, for
instance.

This is used to indicate a formula is a version of another formula.
This will be used to provide a consistent interface for older formulae
versions and replaces the use of `conflicts_with`.

This is a temporary measure until:

- #1862 is merged
- I can a test on `brew uses` against every formula in the official
  taps to verify that exceptions are no longer raised.

…rmulae in recursive dependency expansion""

This reverts commit dc9819b8.

Fixes #1848 by sharing recursive dependency resolution between
dependencies and requirements.

Coincidentally, this also fixes the errors introduced by #1784 that
necessitated it being reverted in #1797.

Users may have this set, breaking grep's output.

Fixes #1430.

Fixes #1821

When a Requirement is converted to a Formula it should be listed under
the runtime dependencies.

This means that a `brew install $ALIAS` records the path accordingly
so  e.g. `Formula#full_installed_specified_name` returns the correct
path.

We're frowning on these now so may as well turn that into code.

These can now be done with just `brew upgrade`, like other upgrades.

Fixes #1818.

also allow higher stable versions with the same version prefix

When the first parameter to inreplace was an array, and the replacement
failed, InreplaceError would end up crashing with an undefined method
exception because the order of operations resulted in super not being
passed the value of the entire inject block.

Fixes #1817.