This helps ensure that tests behave the same in environments (such as
Travis) where PUB_ENVIRONMENT is already set.

This switches pub's tests over to using the stream matchers built into
test, as well as the test_descriptor, test_process, and
shelf_test_handler packages. It uses async/await rather than
scheduled_test's task queue.

This removes a layer of indirection which should make it much easier to
work on pub's test infrastructure, especially for people unfamiliar with
scheduled_test.

* Add metadata to requests to pub.dartlang.org.

This will help pub.dartlang.org better track how packages relate to one
another.

* Fix broken depenency tests.

Those unit tests import pub libraries directly without invoking a
command, so command was throwing an exception. Worse, the Pokemon
exception handler in DependencyValidator was then catching the
StateError, hiding the bug.

Also applied some other changes I suggested.

Pub no longer outputs the "Loading source assets..." line in this case.

The test is failing on the buildbots, and locally.

In particular, "pub get --offline" and "pub cache repair" shouldn't
choke when there are parse failures in the version cache.

Closes #1479

Similarly 98ecbded, this provides better
error messages and faster installation times.

See #1473
See #1477

This sets the stage for adding tests for #1386.

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1664563002 .

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1585513002 .

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1556243002 .

Now instead of just saying how many packages failed to be
reinstalled/reactivated, "pub cache repair" will print a list of those
packages.

This also fixes an issue where "pub cache repair" would incorrectly
return a 0 exit code when packages failed to reactivate.

Closes #1301

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1239623005 .

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1215833002.

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1153643002

R=rnystrom@google.com
BUG=22076

Review URL: https://codereview.chromium.org//899373002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@43737 260f80e4-7a28-3924-810f-c04153c831b5

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//805393002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@42885 260f80e4-7a28-3924-810f-c04153c831b5

This also makes "pub cache repair" repair activated packages, including updating
the binstub format.

R=rnystrom@google.com
BUG=21463

Review URL: https://codereview.chromium.org//745153002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@42055 260f80e4-7a28-3924-810f-c04153c831b5

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//488323002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@39469 260f80e4-7a28-3924-810f-c04153c831b5

RELNOTE=Pub will exclude pre-release versions of the upper bound in "<" constraints.
This matches the behavior of semver in other package managers.
BUG=https://code.google.com/p/dart/issues/detail?id=20302
R=nweiz@google.com

Review URL: https://codereview.chromium.org//432913002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@38806 260f80e4-7a28-3924-810f-c04153c831b5

I also cleaned up a bunch of unused imports.

BUG=https://code.google.com/p/dart/issues/detail?id=20067
R=nweiz@google.com

Review URL: https://codereview.chromium.org//391363004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@38352 260f80e4-7a28-3924-810f-c04153c831b5

R=rnystrom@google.com
BUG=17252

Review URL: https://codereview.chromium.org//363573002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@37915 260f80e4-7a28-3924-810f-c04153c831b5

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//335313004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@37830 260f80e4-7a28-3924-810f-c04153c831b5

R=rnystrom@google.com
BUG=19147

Review URL: https://codereview.chromium.org//311253005

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@37135 260f80e4-7a28-3924-810f-c04153c831b5

BUG=https://code.google.com/p/dart/issues/detail?id=5391
RELNOTE=Add "pub cache repair" command to re-install cached packages.
R=nweiz@google.com

Review URL: https://codereview.chromium.org//228703006

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@35111 260f80e4-7a28-3924-810f-c04153c831b5

BUG=https://code.google.com/p/dart/issues/detail?id=16265
R=nweiz@google.com

Review URL: https://codereview.chromium.org//136063005

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@32575 260f80e4-7a28-3924-810f-c04153c831b5