Merge branch 'liw/yarn-srcdir'

4 files changed, 62 insertions, 1 deletions

diff --git a/NEWS b/NEWS
index ca4d551..4951f4c 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,14 @@ NEWS for cmdtest
 
 This file summarizes changes between releases of cmdtest.
 
+Version 0.10, released UNRELEASED
+---------------------------------
+
+* Yarn now cleans the environment when it runs shell commands for the
+  implementation steps. It also sets the `SRCDIR` environment variable
+  to point at the root of the source tree (the directory where yarn
+  was invoked from).
+
 Version 0.9, released 2013-07-23
 --------------------------------
 
diff --git a/README.yarn b/README.yarn
index 76d57b5..16f7522 100644
--- a/README.yarn
+++ b/README.yarn
@@ -136,6 +136,15 @@ The following keywords are defined.
   The test runner creates a temporary directory, whose name is
   given to the shell code in the `DATADIR` environment variable.
 
+  The test runner sets the `SRCDIR` environment variable to the
+  path to the directory it was invoked from (by convention, the
+  root of the source tree of the project).
+
+  The test runner removes all other environment variables, except
+  `TERM`, `USER`, `USERNAME`, `LOGNAME`, `HOME`, and `PATH`. It also
+  forces `SHELL` set to `/bin/sh`, and `LC_ALL` set to `C`, in order
+  to have as clean an environment as possible for tests to run in.
+
   The shell commands get invoked with `/bin/sh -eu`, and need to
   be written accordingly. Be careful about commands that return a
   non-zero exit code. There will eventually be a library of shell
diff --git a/yarn b/yarn
index 288e23b..6fbd63a 100755
--- a/yarn
+++ b/yarn
@@ -267,6 +267,31 @@ class YarnRunner(cliapp.Application):
 
         return ok
 
+    def clean_env(self):
+        '''Return a clean environment for running tests.'''
+
+        whitelisted = [
+            'TERM',
+            'USER',
+            'USERNAME',
+            'PATH',
+            'HOME',
+            'LOGNAME',
+        ]
+
+        hardcoded = {
+            'SHELL': '/bin/sh',
+            'LC_ALL': 'C',
+        }
+
+        env = {}
+        for key in whitelisted:
+            if key in os.environ:
+                env[key] = os.environ[key]
+        for key in hardcoded:
+            env[key] = hardcoded[key]
+        return env
+
     def run_step(self, datadir, scenario, step, shell_prelude, report_error):
         self.info('Running step "%s %s"' % (step.what, step.text))
         self.ts['step'] = step
@@ -274,8 +299,9 @@ class YarnRunner(cliapp.Application):
 
         m = re.match(step.implementation.regexp, step.text)
         assert m is not None
-        env = os.environ.copy()
+        env = self.clean_env()
         env['DATADIR'] = datadir
+        env['SRCDIR'] = os.getcwd()
         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
new file mode 100755
index 0000000..2ef35c6
--- /dev/null
+++ b/yarn.tests/env.script
@@ -0,0 +1,18 @@
+#!/bin/sh
+
+set -eu
+
+cat << 'EOF' > "$DATADIR/env.yarn"
+    SCENARIO check environment
+    THEN DATADIR is set
+    AND SRCDIR is set
+    AND NOTSET is not set
+
+    IMPLEMENTS THEN (\S+) is set
+    env | grep "^$MATCH_1="
+
+    IMPLEMENTS THEN (\S+) is not set
+    ! env | grep "^$MATCH_1="
+EOF
+
+NOTSET=foo ./run-yarn "$DATADIR/env.yarn"