root/branches/cp3-wsgi-remix/test/webtest.py

"""Extensions to unittest for web frameworks.

Use the WebCase.getPage method to request a page from your HTTP server.

Framework Integration
=====================

If you have control over your server process, you can handle errors
in the server-side of the HTTP conversation a bit better. You must run
both the client (your WebCase tests) and the server in the same process
(but in separate threads, obviously).

When an error occurs in the framework, call server_error. It will print
the traceback to stdout, and keep any assertions you have from running
(the assumption is that, if the server errors, the page output won't be
of further significance to your tests).
"""

import os, sys, time, re
import types
import pprint
import socket
import httplib
import traceback

from unittest import *
from unittest import _TextTestResult


class TerseTestResult(_TextTestResult):
    
    def printErrors(self):
        # Overridden to avoid unnecessary empty line
        if self.errors or self.failures:
            if self.dots or self.showAll:
                self.stream.writeln()
            self.printErrorList('ERROR', self.errors)
            self.printErrorList('FAIL', self.failures)


class TerseTestRunner(TextTestRunner):
    """A test runner class that displays results in textual form."""
    
    def _makeResult(self):
        return TerseTestResult(self.stream, self.descriptions, self.verbosity)
    
    def run(self, test):
        "Run the given test case or test suite."
        # Overridden to remove unnecessary empty lines and separators
        result = self._makeResult()
        startTime = time.time()
        test(result)
        timeTaken = float(time.time() - startTime)
        result.printErrors()
        if not result.wasSuccessful():
            self.stream.write("FAILED (")
            failed, errored = map(len, (result.failures, result.errors))
            if failed:
                self.stream.write("failures=%d" % failed)
            if errored:
                if failed: self.stream.write(", ")
                self.stream.write("errors=%d" % errored)
            self.stream.writeln(")")
        return result


class ReloadingTestLoader(TestLoader):
    
    def loadTestsFromName(self, name, module=None):
        """Return a suite of all tests cases given a string specifier.

        The name may resolve either to a module, a test case class, a
        test method within a test case class, or a callable object which
        returns a TestCase or TestSuite instance.

        The method optionally resolves the names relative to a given module.
        """
        parts = name.split('.')
        if module is None:
            if not parts:
                raise ValueError("incomplete test name: %s" % name)
            else:
                parts_copy = parts[:]
                while parts_copy:
                    target = ".".join(parts_copy)
                    if target in sys.modules:
                        module = reload(sys.modules[target])
                        break
                    else:
                        try:
                            module = __import__(target)
                            break
                        except ImportError:
                            del parts_copy[-1]
                            if not parts_copy:
                                raise
                parts = parts[1:]
        obj = module
        for part in parts:
            obj = getattr(obj, part)
        
        if type(obj) == types.ModuleType:
            return self.loadTestsFromModule(obj)
        elif (isinstance(obj, (type, types.ClassType)) and
              issubclass(obj, TestCase)):
            return self.loadTestsFromTestCase(obj)
        elif type(obj) == types.UnboundMethodType:
            return obj.im_class(obj.__name__)
        elif callable(obj):
            test = obj()
            if not isinstance(test, TestCase) and \
               not isinstance(test, TestSuite):
                raise ValueError("calling %s returned %s, "
                                 "not a test" % (obj,test))
            return test
        else:
            raise ValueError("don't know how to make test from: %s" % obj)


try:
    # On Windows, msvcrt.getch reads a single char without output.
    import msvcrt
    def getchar():
        return msvcrt.getch()
except ImportError:
    # Unix getchr
    import tty, termios
    def getchar():
        fd = sys.stdin.fileno()
        old_settings = termios.tcgetattr(fd)
        try:
            tty.setraw(sys.stdin.fileno())
            ch = sys.stdin.read(1)
        finally:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
        return ch


class WebCase(TestCase):
    HOST = "127.0.0.1"
    PORT = 8000
    HTTP_CONN=httplib.HTTPConnection
    
    def getPage(self, url, headers=None, method="GET", body=None, protocol="HTTP/1.1"):
        """Open the url with debugging support. Return status, headers, body."""
        ServerError.on = False
        
        self.url = url
        result = openURL(url, headers, method, body, self.HOST, self.PORT,
                         self.HTTP_CONN, protocol)
        self.status, self.headers, self.body = result
        
        # Build a list of request cookies from the previous response cookies.
        self.cookies = [('Cookie', v) for k, v in self.headers
                        if k.lower() == 'set-cookie']
        
        if ServerError.on:
            raise ServerError()
        return result
    
    interactive = True
    console_height = 30
    
    def _handlewebError(self, msg):
        print
        print "    ERROR:", msg
        
        if not self.interactive:
            raise self.failureException(msg)
        
        p = "    Show: [B]ody [H]eaders [S]tatus [U]RL; [I]gnore, [R]aise, or sys.e[X]it >> "
        print p,
        while True:
            i = getchar().upper()
            if i not in "BHSUIRX":
                continue
            print i.upper()  # Also prints new line
            if i == "B":
                for x, line in enumerate(self.body.splitlines()):
                    if (x + 1) % self.console_height == 0:
                        # The \r and comma should make the next line overwrite
                        print "<-- More -->\r",
                        m = getchar().lower()
                        # Erase our "More" prompt
                        print "            \r",
                        if m == "q":
                            break
                    print line
            elif i == "H":
                pprint.pprint(self.headers)
            elif i == "S":
                print self.status
            elif i == "U":
                print self.url
            elif i == "I":
                # return without raising the normal exception
                return
            elif i == "R":
                raise self.failureException(msg)
            elif i == "X":
                self.exit()
            print p,
    
    def exit(self):
        sys.exit()
    
    def __call__(self, result=None):
        if result is None:
            result = self.defaultTestResult()
        result.startTest(self)
        testMethod = getattr(self, self._TestCase__testMethodName)
        try:
            try:
                self.setUp()
            except (KeyboardInterrupt, SystemExit):
                raise
            except:
                result.addError(self, self._TestCase__exc_info())
                return
            
            ok = 0
            try:
                testMethod()
                ok = 1
            except self.failureException:
                result.addFailure(self, self._TestCase__exc_info())
            except (KeyboardInterrupt, SystemExit):
                raise
            except:
                result.addError(self, self._TestCase__exc_info())
            
            try:
                self.tearDown()
            except (KeyboardInterrupt, SystemExit):
                raise
            except:
                result.addError(self, self._TestCase__exc_info())
                ok = 0
            if ok:
                result.addSuccess(self)
        finally:
            result.stopTest(self)
    
    def assertStatus(self, status, msg=None):
        """Fail if self.status != status."""
        if isinstance(status, basestring):
            if not self.status == status:
                if msg is None:
                    msg = 'Status (%s) != %s' % (`self.status`, `status`)
                self._handlewebError(msg)
        elif isinstance(status, int):
            code = int(self.status[:3])
            if code != status:
                if msg is None:
                    msg = 'Status (%s) != %s' % (`self.status`, `status`)
                self._handlewebError(msg)
        else:
            # status is a tuple or list.
            match = False
            for s in status:
                if isinstance(s, basestring):
                    if self.status == s:
                        match = True
                        break
                elif int(self.status[:3]) == s:
                    match = True
                    break
            if not match:
                if msg is None:
                    msg = 'Status (%s) not in %s' % (`self.status`, `status`)
                self._handlewebError(msg)
    
    def assertHeader(self, key, value=None, msg=None):
        """Fail if (key, [value]) not in self.headers."""
        lowkey = key.lower()
        for k, v in self.headers:
            if k.lower() == lowkey:
                if value is None or str(value) == v:
                    return v
        
        if msg is None:
            if value is None:
                msg = '%s not in headers' % `key`
            else:
                msg = '%s:%s not in headers' % (`key`, `value`)
        self._handlewebError(msg)
    
    def assertNoHeader(self, key, msg=None):
        """Fail if key in self.headers."""
        lowkey = key.lower()
        matches = [k for k, v in self.headers if k.lower() == lowkey]
        if matches:
            if msg is None:
                msg = '%s in headers' % `key`
            self._handlewebError(msg)
    
    def assertBody(self, value, msg=None):
        """Fail if value != self.body."""
        if value != self.body:
            if msg is None:
                msg = 'expected body:\n%s\n\nactual body:\n%s' % (`value`, `self.body`)
            self._handlewebError(msg)
    
    def assertInBody(self, value, msg=None):
        """Fail if value not in self.body."""
        if value not in self.body:
            if msg is None:
                msg = '%s not in body' % `value`
            self._handlewebError(msg)
    
    def assertNotInBody(self, value, msg=None):
        """Fail if value in self.body."""
        if value in self.body:
            if msg is None:
                msg = '%s found in body' % `value`
            self._handlewebError(msg)
    
    def assertMatchesBody(self, pattern, msg=None, flags=0):
        """Fail if value (a regex pattern) is not in self.body."""
        if re.search(pattern, self.body, flags) is None:
            if msg is None:
                msg = 'No match for %s in body' % `pattern`
            self._handlewebError(msg)


methods_with_bodies = ("POST", "PUT")

def cleanHeaders(headers, method, body, host, port):
    """Return request headers, with required headers added (if missing)."""
    if headers is None:
        headers = []
    
    # Add the required Host request header if not present.
    # [This specifies the host:port of the server, not the client.]
    found = False
    for k, v in headers:
        if k.lower() == 'host':
            found = True
            break
    if not found:
        headers.append(("Host", "%s:%s" % (host, port)))
    
    if method in methods_with_bodies:
        # Stick in default type and length headers if not present
        found = False
        for k, v in headers:
            if k.lower() == 'content-type':
                found = True
                break
        if not found:
            headers.append(("Content-Type", "application/x-www-form-urlencoded"))
            headers.append(("Content-Length", str(len(body or ""))))
    
    return headers


def openURL(url, headers=None, method="GET", body=None,
            host="127.0.0.1", port=8000, http_conn=httplib.HTTPConnection,
            protocol="HTTP/1.1"):
    """Open the given HTTP resource and return status, headers, and body."""
    
    headers = cleanHeaders(headers, method, body, host, port)
    
    # Trying 10 times is simply in case of socket errors.
    # Normal case--it should run once.
    trial = 0
    while trial < 10:
        try:
            conn = http_conn(host, port)
            conn._http_vsn_str = protocol
            conn._http_vsn = int("".join([x for x in protocol if x.isdigit()]))
            
            # skip_accept_encoding argument added in python version 2.4
            if sys.version_info < (2, 4):
                conn.putrequest(method.upper(), url, skip_host=True)
            else:
                conn.putrequest(method.upper(), url, skip_host=True,
                                skip_accept_encoding=True)
            
            for key, value in headers:
                conn.putheader(key, value)
            conn.endheaders()
            
            if body is not None:
                conn.send(body)
            
            # Handle response
            response = conn.getresponse()
            
            status = "%s %s" % (response.status, response.reason)
            
            outheaders = []
            key, value = None, None
            for line in response.msg.headers:
                if line:
                    if line[0] in " \t":
                        value += line.strip()
                    else:
                        if key and value:
                            outheaders.append((key, value))
                        key, value = line.split(":", 1)
                        key = key.strip()
                        value = value.strip()
            if key and value:
                outheaders.append((key, value))
            
            outbody = response.read()
            
            conn.close()
            return status, outheaders, outbody
        except socket.error:
            trial += 1
            if trial >= 10:
                raise
            else:
                time.sleep(0.5)


# Add any exceptions which your web framework handles
# normally (that you don't want server_error to trap).
ignored_exceptions = []

# You'll want set this to True when you can't guarantee
# that each response will immediately follow each request;
# for example, when handling requests via multiple threads.
ignore_all = False

class ServerError(Exception):
    on = False


def server_error(exc=None):
    """Server debug hook. Return True if exception handled, False if ignored.
    
    You probably want to wrap this, so you can still handle an error using
    your framework when it's ignored.
    """
    if exc is None: 
        exc = sys.exc_info()
    
    if ignore_all or exc[0] in ignored_exceptions:
        return False
    else:
        ServerError.on = True
        print
        print "".join(traceback.format_exception(*exc))
        return True