[PATCH 2/3] test: Add `test_emacs_expect_t'.

[David Edmondson]

Add a new test function to allow simpler testing of emacs
functionality.

`test_emacs_expect_t' takes one argument - a list expression to
evaluate. The test passes if the expression returns `t', otherwise it
fails and the output is reported to the tester.
---

Re-worked as Dmitry suggested.

 test/README                  |    8 ++++++++
 test/emacs-test-functions.sh |    9 +++++++++
 test/notmuch-test            |    1 +
 test/test-lib.sh             |   33 +++++++++++++++++++++++++++++++++
 4 files changed, 51 insertions(+), 0 deletions(-)
 create mode 100755 test/emacs-test-functions.sh

diff --git a/test/README b/test/README
index bde6db0..9dbe2ee 100644
--- a/test/README
+++ b/test/README
@@ -189,6 +189,14 @@ library for your script to use.
    tests that may run in the same Emacs instance.  Use `let' instead
    so the scope of the changed variables is limited to a single test.
 
+ test_emacs_expect_t <emacs-lisp-expressions>
+
+  This function executes the provided emacs lisp script within
+  emacs in a manner similar to 'test_emacs'. The expressions should
+  return the value `t' to indicate that the test has passed. If the
+  test does not return `t' then it is considered failed and all data
+  returned by the test is reported to the tester.
+
  test_done
 
    Your test script must have test_done at the end.  Its purpose
diff --git a/test/emacs-test-functions.sh b/test/emacs-test-functions.sh
new file mode 100755
index 0000000..0e1f9fc
--- /dev/null
+++ b/test/emacs-test-functions.sh
@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+test_description="emacs test function sanity"
+. test-lib.sh
+
+test_begin_subtest "emacs test function sanity"
+test_emacs_expect_t 't'
+
+test_done
diff --git a/test/notmuch-test b/test/notmuch-test
index 6a99ae3..d034f99 100755
--- a/test/notmuch-test
+++ b/test/notmuch-test
@@ -52,6 +52,7 @@ TESTS="
   python
   hooks
   argument-parsing
+  emacs-test-functions.sh
 "
 TESTS=${NOTMUCH_TESTS:=$TESTS}
 
diff --git a/test/test-lib.sh b/test/test-lib.sh
index 7c9ce24..4b05760 100644
--- a/test/test-lib.sh
+++ b/test/test-lib.sh
@@ -503,6 +503,39 @@ test_expect_equal_file ()
     fi
 }
 
+test_emacs_expect_t () {
+	test "$#" = 1 || error "bug in the test script: not 1 parameter to test_emacs_expect_t"
+
+	# Run the test.
+	if ! test_skip "$test_subtest_name"
+	then
+		# We cannot call 'test_emacs' in a subshell, because
+		# the setting of EMACS_SERVER would not persist
+		# throughout a sequence of tests, so we use a
+		# temporary file.
+		tmp="$TMPDIR"; if [ -z "$tmp" ]; then tmp=/tmp; fi
+		output="$tmp/test_emacs_output.$$"
+		test_emacs "$1" > "${output}"
+		result=$(cat "${output}")
+		rm -f "${output}"
+	fi
+
+	# Restore state after the test.
+	exec 1>&6 2>&7		# Restore stdout and stderr
+	inside_subtest=
+
+	# Report success/failure.
+	if ! test_skip "$test_subtest_name"
+	then
+		if [ "$result" == t ]
+		then
+			test_ok_ "$test_subtest_name"
+		else
+			test_failure_ "$test_subtest_name" "$(eval printf ${result})"
+		fi
+	fi
+}
+
 NOTMUCH_NEW ()
 {
     notmuch new | grep -v -E -e '^Processed [0-9]*( total)? file|Found [0-9]* total file'
-- 
1.7.7.3