pytest: add capability to log nodes to file

README.md

@@ -206,6 +206,7 @@ be a good reference.
 
 ```
 usage: pytest [--boards] [--hide-output] [--local] [--non-RC] [--self-test]
+              [--log-file-fmt=[LOG_FILE_FMT]]
 
 optional arguments:
   --boards              String list of boards to use for the test, can be
@@ -216,6 +217,16 @@ optional arguments:
   --non-RC              Runs test even if RIOT version under test is not an RC
   --self-test           Tests the testutils rather than running the release
                         tests
+  --log-file-fmt=[LOG_FILE_FMT]
+                        Format for the log file name. The available variables
+                        are: `module`: The module (=specXX) of the test,
+                        `function`: The function (=taskXX) of the test, `node`:
+                        Name of the node (on IoT-LAB the URL of the node,
+                        locally board name + port), `time`: UNIX timestamp at
+                        creation time. If the provided argument is an empty
+                        string the format will be
+                        '{module}-{function}-{node}-{time}.log' and stored in
+                        the current work directory
 ```
 
 Running `tox` will do most of that for you

conftest.py

@@ -6,9 +6,11 @@
 See https://docs.pytest.org/en/stable/fixture.html#conftest-py-sharing-fixture-functions
 """     # noqa: E501
 
+import re
 import os
 import subprocess
 import sys
+import time
 from collections.abc import Iterable
 
 import pytest
@@ -50,6 +52,19 @@ def pytest_addoption(parser):
         "--self-test", action="store_true", default=False,
         help="Tests the testutils rather than running the release tests",
     )
+    parser.addoption(
+        "--log-file-fmt", nargs="?", default=None,
+        type=testutils.pytest.log_file_fmt,
+        help="Format for the log file name. The available variables are: "
+             "`module`: The module (=specXX) of the test, "
+             "`function`: The function (=taskXX) of the test, "
+             "`node`: Name of the node (on IoT-LAB the URL of the node, "
+             "locally board name + port), "
+             "`time`: UNIX timestamp at creation time. "
+             "If the provided argument is an empty string the format will be "
+             "'{module}-{function}-{node}-{time}.log' and stored in the "
+             "current work directory"
+    )
 
 
 def pytest_ignore_collect(path, config):
@@ -116,6 +131,17 @@ def log_nodes(request):
     return not request.config.getoption("--hide-output")
 
 
+@pytest.fixture
+def log_file_fmt(request):
+    """
+    Show output of nodes
+
+    :return: True if output of nodes should be shown, False otherwise
+    """
+    # use reverse, since from outside we most of the time _want_ to log
+    return request.config.getoption("--log-file-fmt")
+
+
 @pytest.fixture
 def local(request):
     """
@@ -202,7 +228,7 @@ def update_env(node, modules=None, cflags=None, port=None, termflags=None):
 
 
 @pytest.fixture
-def riot_ctrl(log_nodes, nodes, riotbase):
+def riot_ctrl(log_nodes, log_file_fmt, nodes, riotbase, request):
     """
     Factory to create RIOTCtrl objects from list nodes provided by nodes
     fixture
@@ -218,6 +244,21 @@ def ctrl(nodes_idx, application_dir, shell_interaction_cls,
         else:
             node = nodes[nodes_idx]
         update_env(node, modules, cflags, port, termflags)
+        # if the nodes are not logged, there is no sense in logging to a file
+        # so check if nodes are logged as well as if they should be logged to a
+        # file
+        if log_nodes and log_file_fmt:
+            if node.env.get("IOTLAB_NODE"):
+                node_name = node.env["IOTLAB_NODE"]
+            else:
+                node_name = "{}-{}".format(
+                    node.board(), re.sub(r'\W+', '-', node.env["PORT"]))
+            node.env["TERMLOG"] = os.path.join(
+                os.getcwd(), log_file_fmt.format(
+                    node=node_name, time=int(time.time()),
+                    **get_namefmt(request)
+                )
+            )
         # need to access private member here isn't possible otherwise sadly :(
         # pylint: disable=W0212
         node._application_directory = os.path.join(riotbase, application_dir)

testutils/pytest.py

@@ -32,6 +32,26 @@ def list_from_string(list_str=None):
     return [v for v in value if v]
 
 
+def log_file_fmt(fmt_str=None):
+    """Get defaulted format string
+
+    >>> import os
+    >>> log_file_fmt(None)
+    >>> os.path.basename(log_file_fmt(''))
+    '{module}-{function}-{node}-{time}.log'
+    >>> log_file_fmt('foobar')
+    'foobar'
+    >>> log_file_fmt('{module}-{function}-{time}-{node}')
+    '{module}-{function}-{time}-{node}'
+    """
+    if fmt_str is not None:
+        if len(fmt_str) > 0:
+            return fmt_str
+        return os.path.join(os.getcwd(),
+                            "{module}-{function}-{node}-{time}.log")
+    return None
+
+
 def check_ssh():
     user, _ = IoTLABExperiment.user_credentials()
     if user is None: