Make yarn set $HOME to an existing directory

3 files changed, 17 insertions, 1 deletions

diff --git a/NEWS b/NEWS
index 4b8bb58..555c610 100644
--- a/NEWS
+++ b/NEWS
@@ -13,6 +13,11 @@ For yarn:
   to include the names of those scenarios only, rather than all
   scenarios. Patch by Pete Fotheringham.
 
+* Yarn now sets `$HOME` to a directory in `$DATADIR`, and creates
+  that directory. This means test suites can assume `$HOME` exists,
+  but don't use the user's real home directory, which is important for
+  test environment hygiene.
+
 For cmdtest:
 
 * The `--test` (`-t`) option should now work again. Thank you
diff --git a/yarn b/yarn
index 24e982b..ef19b94 100755
--- a/yarn
+++ b/yarn
@@ -289,6 +289,9 @@ class YarnRunner(cliapp.Application):
         datadir = self.datadir(tempdir, scenario)
         os.mkdir(datadir)
         self.info('DATADIR is %s' % datadir)
+        homedir = self.homedir(datadir)
+        os.mkdir(homedir)
+        self.info('HOME for tests is %s' % homedir)
 
         assuming = [s for s in scenario.steps if s.what == 'ASSUMING']
         cleanup = [s for s in scenario.steps if s.what == 'FINALLY']
@@ -335,6 +338,9 @@ class YarnRunner(cliapp.Application):
         self.remember_scenario_timing(time.time() - started)
         return ok
 
+    def homedir(self, datadir):
+        return os.path.join(datadir, 'HOME')
+
     def clean_env(self):
         '''Return a clean environment for running tests.'''
 
@@ -349,7 +355,6 @@ class YarnRunner(cliapp.Application):
             'USER': 'tomjon',
             'USERNAME': 'tomjon',
             'LOGNAME': 'tomjon',
-            'HOME': '/this/path/does/not/exist',
         }
 
         env = {}
@@ -384,6 +389,7 @@ class YarnRunner(cliapp.Application):
         env = self.clean_env()
         env['DATADIR'] = datadir
         env['SRCDIR'] = os.getcwd()
+        env['HOME'] = self.homedir(datadir)
         for i, match in enumerate(m.groups('')):
             env['MATCH_%d' % (i+1)] = match
 
diff --git a/yarn.tests/env.script b/yarn.tests/env.script
index d14a21a..d24172d 100755
--- a/yarn.tests/env.script
+++ b/yarn.tests/env.script
@@ -7,6 +7,7 @@ cat << 'EOF' > "$DATADIR/env.yarn"
     THEN DATADIR is set
     AND SRCDIR is set
     AND NOTSET is not set
+    AND HOME is prefixed by DATADIR
 
     IMPLEMENTS THEN (\S+) is set
     env
@@ -14,6 +15,10 @@ cat << 'EOF' > "$DATADIR/env.yarn"
 
     IMPLEMENTS THEN (\S+) is not set
     ! env | grep "^$MATCH_1="
+
+    IMPLEMENTS THEN (\S+) is prefixed by (\S+)
+    x=$(env | sed -n "/^$MATCH_2=/s///p")
+    env | grep "^$MATCH_1=$x/"
 EOF
 
 NOTSET=foo ./run-yarn "$DATADIR/env.yarn"