I ran your tests a couple of times and didn�t see any hangs or crashes (although most of the tests failed). This is on OSX 10.10.2.
'Running tests in 1 Packages'
MCGitFileTreeIssue139Test>>#testWrite [FAIL]
MCGitFileTreeIssue139Test>>#testLoad [FAIL]
MCGitFileTreeIssue139Test>>#testWriteNRead [FAIL]
MCGitFileTreeIssue139Test>>#testRepository [FAIL]
MCGitFileTreeIssue146Test>>#testWrite [FAIL]
MCGitFileTreeIssue146Test>>#testWriteNRead [FAIL]
MCGitFileTreeIssue147Test>>#testWriteNRead [FAIL]
MCGitFileTreeIssue26Test>>#testWriteNRead2 [FAIL]
MCGitFileTreeIssue26Test>>#testWrite [FAIL]
MCGitFileTreeIssue26Test>>#testLoad [FAIL]
MCGitFileTreeIssue26Test>>#testWriteNRead [FAIL]
MCGitFileTreeIssue33Test>>#testWrite [FAIL]
MCGitFileTreeIssue33Test>>#testLoad [FAIL]
MCGitFileTreeIssue33Test>>#testWriteNRead [FAIL]
MCGitFileTreeIssue33Test>>#testRepository [FAIL]
MCGitFileTreeIssue69Test>>#testLoad [FAIL]
MCGitFileTreeIssue72Test>>#testLoad [FAIL]
MCGitFileTreeIssue72Test>>#testWriteNRead [FAIL]
MCGitFileTreeLoaderTest>>#testBaseLoadRepository [FAIL]
MCGitFileTreeLoaderTest>>#testCypressCuisLoad [FAIL]
MCGitFileTreeLoaderTest>>#testIssue74 [FAIL]
MCGitFileTreeLoaderTest>>#testTargetLoad [FAIL]
MCGitFileTreeLoaderTest>>#testTargetLoadRepository [FAIL]
MCGitFileTreeLoaderTest>>#testBaseLoad [FAIL]
MCGitFileTreeLoaderTraitsTest>>#testLoad [FAIL]
MCGitFileTreeTests>>#testStoreReadGitFileTree [31/31]
Finished running 31 Tests