support/testing: add testing for eltest in execline test

The previous commit removes s6-test from the runtime tests. This
commit adds the same test for eltest, which replaced s6-test.

Signed-off-by: J. Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

support/testing/tests/package/test_execline.py

@@ -21,3 +21,8 @@ class TestExecline(infra.basetest.BRTest):
         output, exit_code = self.emulator.run("execlineb -c 'echo hello world'")
         self.assertEqual(exit_code, 0)
         self.assertEqual(output[0].strip(), "hello world")
+
+        _, exit_code = self.emulator.run("mkfifo testpipe")
+        self.assertEqual(exit_code, 0)
+        _, exit_code = self.emulator.run("execlineb -c 'eltest -p testpipe'")
+        self.assertEqual(exit_code, 0)