What version are you running?
4.0
What steps will reproduce the problem?
Run tests without the 'p4' binary installed.
What is the expected output? What do you see instead?
All tests should pass or should be skipped.  Instead, the following tests fails:
GitPerforceClientTests.test_diff_with_exclude_patterns

GitPerforceClientTests.test_diff_with_multiple_commits

GitPerforceClientTests.test_diff_with_rename

GitPerforceClientTests.test_diff_with_deletes

GitPerforceClientTests.test_diff

GitPerforceClientTests.test_diff_exclude_in_subdir

GitPerforceClientTests.test_diff_with_rename_and_changes

GitPerforceClientTests.test_diff_with_exclude_patterns_root_pattern_in_subdir

GitPerforceClientTests.test_diff_with_spaces_in_filename
What operating system are you using?
NA
Attach the debug out from the command.
Example of failure:
------------------------------ Captured log call -------------------------------

19:03:56 DEBUG rbtools.utils.process -- Running: git rev-parse --git-dir

19:03:56 DEBUG rbtools.utils.process -- Running: git config core.bare

19:03:56 DEBUG rbtools.utils.process -- Running: git rev-parse --show-toplevel

19:03:56 DEBUG rbtools.utils.process -- Running: git symbolic-ref -q HEAD

19:03:56 DEBUG rbtools.utils.process -- Running: git show-ref --verify refs/remotes/p4/master

19:03:56 DEBUG rbtools.utils.process -- Running: git config --get git-p4.port

19:03:56 DEBUG rbtools.utils.process -- Running: git rev-parse HEAD

19:03:56 DEBUG rbtools.utils.process -- Running: git add foo.txt

19:03:56 DEBUG rbtools.utils.process -- Running: git commit -m "commit 1"

19:03:56 DEBUG rbtools.utils.process -- Running: git add exclude.txt

19:03:56 DEBUG rbtools.utils.process -- Running: git commit -m "commit 2"

19:03:56 DEBUG rbtools.utils.process -- Running: git rev-parse HEAD

19:03:56 DEBUG rbtools.utils.process -- Running: git rev-parse refs/heads/master

19:03:56 DEBUG rbtools.utils.process -- Running: git branch --remotes

19:03:57 DEBUG rbtools.utils.process -- Running: git rev-parse p4/master

19:03:57 DEBUG rbtools.utils.process -- Running: git rev-list 371df89135df3d355db74dbcb917350a74ed4707 --not --remotes=p4

19:03:57 DEBUG rbtools.utils.process -- Running: git status --porcelain --untracked-files=no --ignore-submodules=dirty

19:03:57 DEBUG rbtools.utils.process -- Running: git version

19:03:57 DEBUG rbtools.utils.process -- Running: git -c core.quotepath=false diff-tree --no-color --no-prefix -r --no-ext-diff 371df89135df3d355db74dbcb917350a74ed4707..79a7ee3c90d1ecbd96a350baede794c822b71ca4

19:03:57 DEBUG rbtools.utils.process -- Running: git -c core.quotepath=false diff --no-color --no-prefix -r -u --no-ext-diff 371df89135df3d355db74dbcb917350a74ed4707..79a7ee3c90d1ecbd96a350baede794c822b71ca4 -- foo.txt

19:03:57 DEBUG rbtools.utils.process -- Running: git log 371df89135df3d355db74dbcb917350a74ed4707

19:03:57 DEBUG rbtools.utils.process -- Running: p4 files //depot/foo.txt@5

19:03:57 DEBUG rbtools.utils.process -- Command not found (p4 files //depot/foo.txt@5)
Please provide any additional information below.
NA