first_stage_test: Refactor the test

This makes it easier to add more tests and the test description is now used by
the test runner.

Signed-off-by: Marc Hartmayer <[email protected]>

Author: mhartmay

tests/first_stage_test.py

@@ -1,5 +1,3 @@
-import subprocess
-
 import mitogen.core
 import mitogen.parent
 from mitogen.core import b
@@ -16,29 +14,39 @@ class CommandLineTest(testlib.RouterMixin, testlib.TestCase):
     #   * 2.7 starting 3.x
     #   * 3.x starting 2.7
 
-    def test_valid_syntax(self):
+    def setUp(self):
+        super(CommandLineTest, self).setUp()
         options = mitogen.parent.Options(max_message_size=123)
         conn = mitogen.parent.Connection(options, self.router)
         conn.context = mitogen.core.Context(None, 123)
-        args = conn.get_boot_command()
+        self.args = conn.get_boot_command()
+        self.preamble = conn.get_preamble()
+        self.conn = conn
+
+    def test_valid_syntax(self):
+        """Test valid syntax
+
+        The boot command should write an ECO marker to stdout, read the
+        preamble from stdin, then execute it.
+
+        This test attaches /dev/zero to stdin to create a specific failure
 
-        # The boot command should write an ECO marker to stdout, read the
-        # preamble from stdin, then execute it.
+        1. Fork child reads <compressed preamble size> bytes of NUL (`b'\0'`)
+        2. Fork child crashes (trying to decompress the junk data)
+        3. Fork child's file descriptors (write pipes) are closed by the OS
+        4. Fork parent does `dup(<read pipe>, <stdin>)` and `exec(<python>)`
+        5. Python reads `b''` (i.e. EOF) from stdin (a closed pipe)
+        6. Python runs `''` (a valid script) and exits with success
 
-        # This test attaches /dev/zero to stdin to create a specific failure
-        # 1. Fork child reads <compressed preamble size> bytes of NUL (`b'\0'`)
-        # 2. Fork child crashes (trying to decompress the junk data)
-        # 3. Fork child's file descriptors (write pipes) are closed by the OS
-        # 4. Fork parent does `dup(<read pipe>, <stdin>)` and `exec(<python>)`
-        # 5. Python reads `b''` (i.e. EOF) from stdin (a closed pipe)
-        # 6. Python runs `''` (a valid script) and exits with success
+        """
 
         fp = open("/dev/zero", "r")
         try:
-            proc = subprocess.Popen(args,
+            proc = testlib.subprocess.Popen(
+                self.args,
                 stdin=fp,
-                stdout=subprocess.PIPE,
-                stderr=subprocess.PIPE,
+                stdout=testlib.subprocess.PIPE,
+                stderr=testlib.subprocess.PIPE,
             )
             stdout, stderr = proc.communicate()
             self.assertEqual(0, proc.returncode)