[enh] More helpers for common IO operations (#141)

locales/en.json

@@ -36,5 +36,18 @@
     "unknown_user": "Unknown '{user}' user",
     "values_mismatch": "Values don't match",
     "warning": "Warning:",
-    "websocket_request_expected": "Expected a WebSocket request"
+    "websocket_request_expected": "Expected a WebSocket request",
+    "cannot_open_file": "Could not open file {file:s} (reason: {error:s})",
+    "cannot_write_file": "Could not write file {file:s} (reason: {error:s})",
+    "unknown_error_reading_file": "Unknown error while trying to read file {file:s}",
+    "corrupted_json": "Corrupted json read from {ressource:s} (reason: {error:s})",
+    "error_writing_file":  "Error when writing file {file:s}: {error:s}",
+    "error_removing": "Error when removing {path:s}: {error:s}",
+    "error_changing_file_permissions": "Error when changing permissions for {path:s}: {error:s}",
+    "invalid_url": "Invalid url {url:s} (does this site exists ?)",
+    "download_ssl_error": "SSL error when connecting to {url:s}",
+    "download_timeout": "{url:s} took too long to answer, gave up.",
+    "download_unknown_error": "Error when downloading data from {url:s} : {error:s}",
+    "download_bad_status_code": "{url:s} returned status code {code:s}",
+    "command_unknown": "Command '{command:s}' unknown ?"
 }

moulinette/utils/filesystem.py

@@ -1,13 +1,140 @@
 import os
 import errno
 import shutil
+import json
+import grp
 from pwd import getpwnam
 
 from moulinette.core import MoulinetteError
 
-
 # Files & directories --------------------------------------------------
 
+def read_file(file_path):
+    """
+    Read a regular text file
+
+    Keyword argument:
+        file_path -- Path to the text file
+    """
+    assert isinstance(file_path, basestring)
+
+    # Check file exists
+    if not os.path.isfile(file_path):
+        raise MoulinetteError(errno.ENOENT,
+                              m18n.g('file_not_exist', path=file_path))
+
+    # Open file and read content
+    try:
+        with open(file_path, "r") as f:
+            file_content = f.read()
+    except IOError as e:
+        raise MoulinetteError(errno.EACCES,
+                              m18n.g('cannot_open_file',
+                                     file=file_path, error=str(e)))
+    except Exception as e:
+        raise MoulinetteError(errno.EIO,
+                              m18n.g('error_reading_file',
+                                     file=file_path, error=str(e)))
+
+    return file_content
+
+
+def read_json(file_path):
+    """
+    Read a json file
+
+    Keyword argument:
+        file_path -- Path to the json file
+    """
+
+    # Read file
+    file_content = read_file(file_path)
+
+    # Try to load json to check if it's syntaxically correct
+    try:
+        loaded_json = json.loads(file_content)
+    except ValueError as e:
+        raise MoulinetteError(errno.EINVAL,
+                              m18n.g('corrupted_json',
+                                     ressource=file_path, error=str(e)))
+
+    return loaded_json
+
+
+def write_to_file(file_path, data, file_mode="w"):
+    """
+    Write a single string or a list of string to a text file.
+    The text file will be overwritten by default.
+
+    Keyword argument:
+        file_path -- Path to the output file
+        data -- The data to write (must be a string or list of string)
+        file_mode -- Mode used when writing the file. Option meant to be used
+        by append_to_file to avoid duplicating the code of this function.
+    """
+    assert isinstance(data, basestring) or isinstance(data, list)
+    assert not os.path.isdir(file_path)
+    assert os.path.isdir(os.path.dirname(file_path))
+
+    # If data is a list, check elements are strings and build a single string
+    if not isinstance(data, basestring):
+        for element in data:
+            assert isinstance(element, basestring)
+        data = '\n'.join(data)
+
+    try:
+        with open(file_path, file_mode) as f:
+            f.write(data)
+    except IOError as e:
+        raise MoulinetteError(errno.EACCES,
+                              m18n.g('cannot_write_file',
+                                     file=file_path, error=str(e)))
+    except Exception as e:
+        raise MoulinetteError(errno.EIO,
+                              m18n.g('error_writing_file',
+                                     file=file_path, error=str(e)))
+
+def append_to_file(file_path, data):
+    """
+    Append a single string or a list of string to a text file.
+
+    Keyword argument:
+        file_path -- Path to the output file
+        data -- The data to write (must be a string or list of string)
+    """
+
+    write_to_file(file_path, data, file_mode="a")
+
+
+def write_to_json(file_path, data):
+    """
+    Write a dictionnary or a list to a json file
+
+    Keyword argument:
+        file_path -- Path to the output json file
+        data -- The data to write (must be a dict or a list)
+    """
+
+    # Assumptions
+    assert isinstance(file_path, basestring)
+    assert isinstance(data, dict) or isinstance(data, list)
+    assert not os.path.isdir(file_path)
+    assert os.path.isdir(os.path.dirname(file_path))
+
+    # Write dict to file
+    try:
+        with open(file_path, "w") as f:
+            json.dump(data, f)
+    except IOError as e:
+        raise MoulinetteError(errno.EACCES,
+                              m18n.g('cannot_write_file',
+                                     file=file_path, error=str(e)))
+    except Exception as e:
+        raise MoulinetteError(errno.EIO,
+                              m18n.g('_error_writing_file',
+                                     file=file_path, error=str(e)))
+
+
 def mkdir(path, mode=0777, parents=False, uid=None, gid=None, force=False):
     """Create a directory with optional features
 
@@ -70,13 +197,14 @@ def chown(path, uid=None, gid=None, recursive=False):
         uid = -1
     if isinstance(gid, basestring):
         try:
-            gid = getpwnam(gid).gr_gid
+            gid = grp.getgrnam(gid).gr_gid
         except KeyError:
             raise MoulinetteError(errno.EINVAL,
                                   m18n.g('unknown_group', group=gid))
     elif gid is None:
         gid = -1
 
+    try:
         os.chown(path, uid, gid)
         if recursive and os.path.isdir(path):
             for root, dirs, files in os.walk(path):
@@ -84,6 +212,10 @@ def chown(path, uid=None, gid=None, recursive=False):
                     os.chown(os.path.join(root, d), uid, gid)
                 for f in files:
                     os.chown(os.path.join(root, f), uid, gid)
+    except Exception as e:
+        raise MoulinetteError(errno.EIO,
+                              m18n.g('error_changing_file_permissions',
+                                     path=path, error=str(e)))
 
 
 def chmod(path, mode, fmode=None, recursive=False):
@@ -95,6 +227,8 @@ def chmod(path, mode, fmode=None, recursive=False):
         - recursive -- Operate on path recursively
 
     """
+
+    try:
         os.chmod(path, mode)
         if recursive and os.path.isdir(path):
             if fmode is None:
@@ -104,6 +238,10 @@ def chmod(path, mode, fmode=None, recursive=False):
                     os.chmod(os.path.join(root, d), mode)
                 for f in files:
                     os.chmod(os.path.join(root, f), fmode)
+    except Exception as e:
+        raise MoulinetteError(errno.EIO,
+                              m18n.g('error_changing_file_permissions',
+                                     path=path, error=str(e)))
 
 
 def rm(path, recursive=False, force=False):
@@ -120,6 +258,8 @@ def rm(path, recursive=False, force=False):
     else:
         try:
             os.remove(path)
-        except OSError:
+        except OSError as e:
             if not force:
-                raise
+                raise MoulinetteError(errno.EIO,
+                                      m18n.g('error_removing',
+                                             path=path, error=str(e)))

moulinette/utils/network.py

@@ -0,0 +1,61 @@
+import errno
+import requests
+import json
+
+from moulinette.core import MoulinetteError
+
+
+def download_text(url, timeout=30):
+    """
+    Download text from a url and returns the raw text
+
+    Keyword argument:
+        url -- The url to download the data from
+        timeout -- Number of seconds allowed for download to effectively start
+        before giving up
+    """
+    # Assumptions
+    assert isinstance(url, str)
+
+    # Download file
+    try:
+        r = requests.get(url, timeout=timeout)
+    # Invalid URL
+    except requests.exceptions.ConnectionError:
+        raise MoulinetteError(errno.EBADE,
+                              m18n.g('invalid_url', url=url))
+    # SSL exceptions
+    except requests.exceptions.SSLError:
+        raise MoulinetteError(errno.EBADE,
+                              m18n.g('download_ssl_error', url=url))
+    # Timeout exceptions
+    except requests.exceptions.Timeout:
+        raise MoulinetteError(errno.ETIME,
+                              m18n.g('download_timeout', url=url))
+    # Unknown stuff
+    except Exception as e:
+        raise MoulinetteError(errno.ECONNRESET,
+                              m18n.g('download_unknown_error',
+                                     url=url, error=str(e)))
+    # Assume error if status code is not 200 (OK)
+    if r.status_code != 200:
+        raise MoulinetteError(errno.EBADE,
+                              m18n.g('download_bad_status_code',
+                                     url=url, code=str(r.status_code)))
+
+    return r.text
+
+
+def download_json(url, timeout=30):
+
+    # Fetch the data
+    text = download_text(url, timeout)
+
+    # Try to load json to check if it's syntaxically correct
+    try:
+        loaded_json = json.loads(text)
+    except ValueError:
+        raise MoulinetteError(errno.EINVAL,
+                              m18n.g('corrupted_json', ressource=url))
+
+    return loaded_json

moulinette/utils/process.py

@@ -1,6 +1,9 @@
+import errno
 import time
 import subprocess
 
+from moulinette.core import MoulinetteError
+
 # This import is unused in this file. It will be deleted in future (W0611 PEP8),
 # but for the momment we keep it due to yunohost moulinette script that used
 # process.quote syntax to access this module !
@@ -102,8 +105,8 @@ def call_async_output(args, callback, **kwargs):
 
 # Call multiple commands -----------------------------------------------
 
-def check_commands(cmds, raise_on_error=False, callback=None,
-                   separate_stderr=False, shell=True, **kwargs):
+def run_commands(cmds, callback=None, separate_stderr=False, shell=True,
+                  **kwargs):
     """Run multiple commands with error management
 
     Run a list of commands and allow to manage how to treat errors either
@@ -127,9 +130,9 @@ def check_commands(cmds, raise_on_error=False, callback=None,
 
     Keyword arguments:
         - cmds -- List of commands to run
-        - raise_on_error -- True to raise a CalledProcessError on error if
-            no callback is provided
-        - callback -- Method or object to call on command failure
+        - callback -- Method or object to call on command failure. If no
+                      callback is given, a "subprocess.CalledProcessError"
+                      will be raised in case of command failure.
         - separate_stderr -- True to return command output as a 2-tuple
         - **kwargs -- Additional arguments for the Popen constructor
 
@@ -137,20 +140,19 @@ def check_commands(cmds, raise_on_error=False, callback=None,
         Number of failed commands
 
     """
+
+    # stdout and stderr are specified by this code later, so they cannot be
+    # overriden by user input
     for a in ['stdout', 'stderr']:
         if a in kwargs:
             raise ValueError('%s argument not allowed, '
                              'it will be overridden.' % a)
-    error = 0
 
+    # If no callback specified...
     if callback is None:
-        if raise_on_error:
-            # Raise on command failure
+        # Raise CalledProcessError on command failure
         def callback(r, c, o):
             raise CalledProcessError(r, c, o)
-        else:
-            # Continue commands execution
-            callback = lambda r, c, o: True
     elif not callable(callback):
         raise ValueError('callback argument must be callable')
 
@@ -163,9 +165,12 @@ def check_commands(cmds, raise_on_error=False, callback=None,
         _get_output = lambda o, e: o
 
     # Iterate over commands
+    error = 0
     for cmd in cmds:
+
         process = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                                    stderr=_stderr, shell=shell, **kwargs)
+
         output = _get_output(*process.communicate())
         retcode = process.poll()
         if retcode:

moulinette/utils/tests/conftest.py

@@ -0,0 +1,96 @@
+import sys
+import moulinette
+
+sys.path.append("..")
+
+###############################################################################
+#   Tweak moulinette init to have yunohost namespace                          #
+###############################################################################
+
+
+old_init = moulinette.core.Moulinette18n.__init__
+def monkey_path_i18n_init(self, package, default_locale="en"):
+    old_init(self, package, default_locale)
+    self.load_namespace("moulinette")
+moulinette.core.Moulinette18n.__init__ = monkey_path_i18n_init
+
+
+###############################################################################
+#   Tweak translator to raise exceptions if string keys are not defined       #
+###############################################################################
+
+
+old_translate = moulinette.core.Translator.translate
+def new_translate(self, key, *args, **kwargs):
+
+    if key not in self._translations[self.default_locale].keys():
+        raise KeyError("Unable to retrieve key %s for default locale !" % key)
+
+    return old_translate(self, key, *args, **kwargs)
+moulinette.core.Translator.translate = new_translate
+
+def new_m18nn(self, key, *args, **kwargs):
+    return self._global.translate(key, *args, **kwargs)
+moulinette.core.Moulinette18n.g = new_m18nn
+
+
+###############################################################################
+#   Init the moulinette to have the cli loggers stuff                         #
+###############################################################################
+
+
+def pytest_cmdline_main(config):
+    """Configure logging and initialize the moulinette"""
+    # Define loggers handlers
+    handlers = set(['tty'])
+    root_handlers = set(handlers)
+
+    # Define loggers level
+    level = 'INFO'
+    tty_level = 'SUCCESS'
+
+    # Custom logging configuration
+    logging = {
+        'version': 1,
+        'disable_existing_loggers': True,
+        'formatters': {
+            'tty-debug': {
+                'format': '%(relativeCreated)-4d %(fmessage)s'
+            },
+            'precise': {
+                'format': '%(asctime)-15s %(levelname)-8s %(name)s %(funcName)s - %(fmessage)s'
+            },
+        },
+        'filters': {
+            'action': {
+                '()': 'moulinette.utils.log.ActionFilter',
+            },
+        },
+        'handlers': {
+            'tty': {
+                'level': tty_level,
+                'class': 'moulinette.interfaces.cli.TTYHandler',
+                'formatter': '',
+            },
+        },
+        'loggers': {
+            'moulinette': {
+                'level': level,
+                'handlers': [],
+                'propagate': True,
+            },
+            'moulinette.interface': {
+                'level': level,
+                'handlers': handlers,
+                'propagate': False,
+            },
+        },
+        'root': {
+            'level': level,
+            'handlers': root_handlers,
+        },
+    }
+
+    # Initialize moulinette
+    moulinette.init(logging_config=logging, _from_source=False)
+

moulinette/utils/tests/test_filesystem.py

@@ -0,0 +1,299 @@
+
+# General python lib
+import os
+import pwd
+import pytest
+import requests
+import requests_mock
+
+# Moulinette specific
+from moulinette.core import MoulinetteError
+from moulinette.utils.filesystem import (
+        read_file, read_json,
+        write_to_file, append_to_file, write_to_json,
+        rm,
+        chmod, chown)
+
+# We define a dummy context with test folders and files
+
+TEST_URL = "https://some.test.url/yolo.txt"
+TMP_TEST_DIR = "/tmp/test_iohelpers"
+TMP_TEST_FILE = "%s/foofile" % TMP_TEST_DIR
+TMP_TEST_JSON = "%s/barjson" % TMP_TEST_DIR
+NON_ROOT_USER = "admin"
+NON_ROOT_GROUP = "mail"
+
+
+def setup_function(function):
+
+    os.system("rm -rf %s" % TMP_TEST_DIR)
+    os.system("mkdir %s" % TMP_TEST_DIR)
+    os.system("echo 'foo\nbar' > %s" % TMP_TEST_FILE)
+    os.system("echo '{ \"foo\":\"bar\" }' > %s" % TMP_TEST_JSON)
+    os.system("chmod 700 %s" % TMP_TEST_FILE)
+    os.system("chmod 700 %s" % TMP_TEST_JSON)
+
+
+def teardown_function(function):
+
+    os.seteuid(0)
+    os.system("rm -rf /tmp/test_iohelpers/")
+
+
+# Helper to try stuff as non-root
+def switch_to_non_root_user():
+
+    nonrootuser = pwd.getpwnam(NON_ROOT_USER).pw_uid
+    os.seteuid(nonrootuser)
+
+
+###############################################################################
+#   Test file read                                                            #
+###############################################################################
+
+
+def test_read_file():
+
+    content = read_file(TMP_TEST_FILE)
+    assert content == "foo\nbar\n"
+
+
+def test_read_file_badfile():
+
+    with pytest.raises(MoulinetteError):
+        read_file(TMP_TEST_FILE+"nope")
+
+
+def test_read_file_badpermissions():
+
+    switch_to_non_root_user()
+    with pytest.raises(MoulinetteError):
+        read_file(TMP_TEST_FILE)
+
+
+def test_read_json():
+
+    content = read_json(TMP_TEST_JSON)
+    assert "foo" in content.keys()
+    assert content["foo"] == "bar"
+
+
+def test_read_json_badjson():
+
+    os.system("echo '{ not valid json lol }' > %s" % TMP_TEST_JSON)
+
+    with pytest.raises(MoulinetteError):
+        read_json(TMP_TEST_JSON)
+
+
+###############################################################################
+#   Test file write                                                           #
+###############################################################################
+
+
+def test_write_to_existing_file():
+
+    assert os.path.exists(TMP_TEST_FILE)
+    write_to_file(TMP_TEST_FILE, "yolo\nswag")
+    assert read_file(TMP_TEST_FILE) == "yolo\nswag"
+
+
+def test_write_to_new_file():
+
+    new_file = "%s/barfile" % TMP_TEST_DIR
+    assert not os.path.exists(new_file)
+    write_to_file(new_file, "yolo\nswag")
+    assert os.path.exists(new_file)
+    assert read_file(new_file) == "yolo\nswag"
+
+
+def test_write_to_existing_file_badpermissions():
+
+    assert os.path.exists(TMP_TEST_FILE)
+    switch_to_non_root_user()
+    with pytest.raises(MoulinetteError):
+        write_to_file(TMP_TEST_FILE, "yolo\nswag")
+
+
+def test_write_to_new_file_badpermissions():
+
+    switch_to_non_root_user()
+    new_file = "%s/barfile" % TMP_TEST_DIR
+    assert not os.path.exists(new_file)
+    with pytest.raises(MoulinetteError):
+        write_to_file(new_file, "yolo\nswag")
+
+
+def test_write_to_folder():
+
+    with pytest.raises(AssertionError):
+        write_to_file(TMP_TEST_DIR, "yolo\nswag")
+
+
+def test_write_inside_nonexistent_folder():
+
+    with pytest.raises(AssertionError):
+        write_to_file("/toto/test", "yolo\nswag")
+
+
+def test_write_to_file_with_a_list():
+
+    assert os.path.exists(TMP_TEST_FILE)
+    write_to_file(TMP_TEST_FILE, ["yolo", "swag"])
+    assert read_file(TMP_TEST_FILE) == "yolo\nswag"
+
+
+def test_append_to_existing_file():
+
+    assert os.path.exists(TMP_TEST_FILE)
+    append_to_file(TMP_TEST_FILE, "yolo\nswag")
+    assert read_file(TMP_TEST_FILE) == "foo\nbar\nyolo\nswag"
+
+
+def test_append_to_new_file():
+
+    new_file = "%s/barfile" % TMP_TEST_DIR
+    assert not os.path.exists(new_file)
+    append_to_file(new_file, "yolo\nswag")
+    assert os.path.exists(new_file)
+    assert read_file(new_file) == "yolo\nswag"
+
+
+def text_write_dict_to_json():
+
+    dummy_dict = {"foo": 42, "bar": ["a", "b", "c"]}
+    write_to_json(TMP_TEST_FILE, dummy_dict)
+    j = read_json(TMP_TEST_FILE)
+    assert "foo" in j.keys()
+    assert "bar" in j.keys()
+    assert j["foo"] == 42
+    assert j["bar"] == ["a", "b", "c"]
+    assert read_file(TMP_TEST_FILE) == "foo\nbar\nyolo\nswag"
+
+
+def text_write_list_to_json():
+
+    dummy_list = ["foo", "bar", "baz"]
+    write_to_json(TMP_TEST_FILE, dummy_list)
+    j = read_json(TMP_TEST_FILE)
+    assert j == ["foo", "bar", "baz"]
+
+
+def test_write_to_json_badpermissions():
+
+    switch_to_non_root_user()
+    dummy_dict = {"foo": 42, "bar": ["a", "b", "c"]}
+    with pytest.raises(MoulinetteError):
+        write_to_json(TMP_TEST_FILE, dummy_dict)
+
+
+def test_write_json_inside_nonexistent_folder():
+
+    with pytest.raises(AssertionError):
+        write_to_file("/toto/test.json", ["a", "b"])
+
+
+###############################################################################
+#   Test file remove                                                          #
+###############################################################################
+
+
+def test_remove_file():
+
+    rm(TMP_TEST_FILE)
+    assert not os.path.exists(TMP_TEST_FILE)
+
+
+def test_remove_file_badpermissions():
+
+    switch_to_non_root_user()
+    with pytest.raises(MoulinetteError):
+        rm(TMP_TEST_FILE)
+
+
+def test_remove_directory():
+
+    rm(TMP_TEST_DIR, recursive=True)
+    assert not os.path.exists(TMP_TEST_DIR)
+
+
+###############################################################################
+#   Test permission change                                                    #
+###############################################################################
+
+
+def get_permissions(file_path):
+    from stat import ST_MODE
+    return (pwd.getpwuid(os.stat(file_path).st_uid).pw_name,
+            pwd.getpwuid(os.stat(file_path).st_gid).pw_name,
+            oct(os.stat(file_path)[ST_MODE])[-3:])
+
+
+# FIXME - should split the test of chown / chmod as independent tests
+def set_permissions(f, owner, group, perms):
+    chown(f, owner, group)
+    chmod(f, perms)
+
+
+def test_setpermissions_file():
+
+    # Check we're at the default permissions
+    assert get_permissions(TMP_TEST_FILE) == ("root", "root", "700")
+
+    # Change the permissions
+    set_permissions(TMP_TEST_FILE, NON_ROOT_USER, NON_ROOT_GROUP, 0111)
+
+    # Check the permissions got changed
+    assert get_permissions(TMP_TEST_FILE) == (NON_ROOT_USER, NON_ROOT_GROUP, "111")
+
+    # Change the permissions again
+    set_permissions(TMP_TEST_FILE, "root", "root", 0777)
+
+    # Check the permissions got changed
+    assert get_permissions(TMP_TEST_FILE) == ("root", "root", "777")
+
+
+def test_setpermissions_directory():
+
+    # Check we're at the default permissions
+    assert get_permissions(TMP_TEST_DIR) == ("root", "root", "755")
+
+    # Change the permissions
+    set_permissions(TMP_TEST_DIR, NON_ROOT_USER, NON_ROOT_GROUP, 0111)
+
+    # Check the permissions got changed
+    assert get_permissions(TMP_TEST_DIR) == (NON_ROOT_USER, NON_ROOT_GROUP, "111")
+
+    # Change the permissions again
+    set_permissions(TMP_TEST_DIR, "root", "root", 0777)
+
+    # Check the permissions got changed
+    assert get_permissions(TMP_TEST_DIR) == ("root", "root", "777")
+
+
+def test_setpermissions_permissiondenied():
+
+    switch_to_non_root_user()
+
+    with pytest.raises(MoulinetteError):
+        set_permissions(TMP_TEST_FILE, NON_ROOT_USER, NON_ROOT_GROUP, 0111)
+
+
+def test_setpermissions_badfile():
+
+    with pytest.raises(MoulinetteError):
+        set_permissions("/foo/bar/yolo", NON_ROOT_USER, NON_ROOT_GROUP, 0111)
+
+
+def test_setpermissions_baduser():
+
+    with pytest.raises(MoulinetteError):
+        set_permissions(TMP_TEST_FILE, "foo", NON_ROOT_GROUP, 0111)
+
+
+def test_setpermissions_badgroup():
+
+    with pytest.raises(MoulinetteError):
+        set_permissions(TMP_TEST_FILE, NON_ROOT_USER, "foo", 0111)
+
+

moulinette/utils/tests/test_network.py

@@ -0,0 +1,92 @@
+
+# General python lib
+import os
+import pwd
+import pytest
+import requests
+import requests_mock
+
+# Moulinette specific
+from moulinette.core import MoulinetteError
+from moulinette.utils.network import download_text, download_json
+
+# We define a dummy context with test folders and files
+
+TEST_URL = "https://some.test.url/yolo.txt"
+
+def setup_function(function):
+
+    pass
+
+def teardown_function(function):
+
+    pass
+
+###############################################################################
+#   Test download                                                             #
+###############################################################################
+
+
+def test_download():
+
+    with requests_mock.Mocker() as m:
+        m.register_uri("GET", TEST_URL, text='some text')
+
+        fetched_text = download_text(TEST_URL)
+
+    assert fetched_text == "some text"
+
+
+def test_download_badurl():
+
+    with pytest.raises(MoulinetteError):
+        download_text(TEST_URL)
+
+
+def test_download_404():
+
+    with requests_mock.Mocker() as m:
+        m.register_uri("GET", TEST_URL, status_code=404)
+
+        with pytest.raises(MoulinetteError):
+            download_text(TEST_URL)
+
+
+def test_download_sslerror():
+
+    with requests_mock.Mocker() as m:
+        m.register_uri("GET", TEST_URL, exc=requests.exceptions.SSLError)
+
+        with pytest.raises(MoulinetteError):
+            download_text(TEST_URL)
+
+
+def test_download_timeout():
+
+    with requests_mock.Mocker() as m:
+        m.register_uri("GET", TEST_URL, exc=requests.exceptions.ConnectTimeout)
+
+        with pytest.raises(MoulinetteError):
+            download_text(TEST_URL)
+
+
+def test_download_json():
+
+    with requests_mock.Mocker() as m:
+        m.register_uri("GET", TEST_URL, text='{ "foo":"bar" }')
+
+        fetched_json = download_json(TEST_URL)
+
+    assert "foo" in fetched_json.keys()
+    assert fetched_json["foo"] == "bar"
+
+
+def test_download_json_badjson():
+
+    with requests_mock.Mocker() as m:
+        m.register_uri("GET", TEST_URL, text='{ not json lol }')
+
+        with pytest.raises(MoulinetteError):
+            download_json(TEST_URL)
+
+

moulinette/utils/tests/test_process.py

@@ -0,0 +1,66 @@
+# General python lib
+import os
+import pwd
+import pytest
+
+# Moulinette specific
+from subprocess import CalledProcessError
+from moulinette.utils.process import run_commands
+
+# We define a dummy context with test folders and files
+
+TMP_TEST_DIR = "/tmp/test_iohelpers"
+TMP_TEST_FILE = "%s/foofile" % TMP_TEST_DIR
+NON_ROOT_USER = "admin"
+NON_ROOT_GROUP = "mail"
+
+
+def setup_function(function):
+
+    os.system("rm -rf %s" % TMP_TEST_DIR)
+    os.system("mkdir %s" % TMP_TEST_DIR)
+    os.system("echo 'foo\nbar' > %s" % TMP_TEST_FILE)
+    os.system("chmod 700 %s" % TMP_TEST_FILE)
+
+
+def teardown_function(function):
+
+    os.seteuid(0)
+    os.system("rm -rf /tmp/test_iohelpers/")
+
+
+# Helper to try stuff as non-root
+def switch_to_non_root_user():
+
+    nonrootuser = pwd.getpwnam(NON_ROOT_USER).pw_uid
+    os.seteuid(nonrootuser)
+
+###############################################################################
+#   Test run shell commands                                                   #
+###############################################################################
+
+def test_run_shell_command_list():
+
+    commands = ["rm -f %s" % TMP_TEST_FILE]
+
+    assert os.path.exists(TMP_TEST_FILE)
+    run_commands(commands)
+    assert not os.path.exists(TMP_TEST_FILE)
+
+
+def test_run_shell_badcommand():
+
+    commands = ["yolo swag"]
+
+    with pytest.raises(CalledProcessError):
+        run_commands(commands)
+
+
+def test_run_shell_command_badpermissions():
+
+    commands = ["rm -f %s" % TMP_TEST_FILE]
+
+    switch_to_non_root_user()
+    with pytest.raises(CalledProcessError):
+        run_commands(commands)
+