python: Document CHDR Test Generation

The script_test.py script is used to generate data .cpp files from a
wireshark trace for the C++ CHDR Parser tests. This commit expands the
script to also generate the data .py files for the Python CHDR Parser
tests.

Signed-off-by: Samuel O'Brien <sam.obrien@ni.com>

host/tests/common/chdr_resource/README.md

@@ -21,4 +21,4 @@ It contains many Data packets, as well as some Stream Status and Stream Command
 5. Save the trace with a descriptive name in the `host/tests/common/chdr_resource` directory as a `.c` file
 6. In the `host/tests/common/chdr_resource` directory, run `./format_trace.py {filename}`, where `{filename}` is the name of the `.c` file you save the trace as.
 
-This will create a `.cpp` file of the same name, which contains the trace data inside a namespace matching the filename. The trace can now be accessed in unit tests with `#include <chdr_resource/{filename}.cpp>`.
+This will create a `.cpp` file and a `.py` file of the same name, which contains the trace data inside a namespace matching the filename. The trace can now be accessed in unit tests with `#include <chdr_resource/{filename}.cpp>` in C++ and `from chdr_resource import {filename}` in Python.

host/tests/common/chdr_resource/format_trace.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright 2017 Ettus Research, a National Instruments Company
+# Copyright 2020 Ettus Research, a National Instruments Brand
 #
 # SPDX-License-Identifier: GPL-3.0-or-later
 #
@@ -10,20 +10,21 @@ import re
 
 if len(sys.argv) < 2:
     print("Please supply an input filename!")
-    exit()
+    sys.exit()
 
 input_arg = sys.argv[1]
 filename_pat = re.compile(r"(.*)\.c")
 m = filename_pat.match(input_arg)
 if not m:
     print("Please supply a .c file as input!")
-    exit()
+    sys.exit()
 filename = m.group(1)
 
 input_file = open(filename + ".c", "r")
-output_file = open(filename + ".cpp", "w")
+cpp_file = open(filename + ".cpp", "w")
+python_file = open(filename + ".py", "w")
 
-output_header = """//
+OUTPUT_HEADER_CPP = """//
 // Copyright 2020 Ettus Research, a National Instruments Brand
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
@@ -33,6 +34,14 @@ output_header = """//
 
 """
 
+OUTPUT_HEADER_PYTHON = """#
+# Copyright 2020 Ettus Research, a National Instruments Company
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+
+"""
+
 # Matches a line defining a new packet, e.g
 # char peer1_19[] = { /* Packet 3153 */
 # Group 1 is the array name, e.g. "peer1_19"
@@ -40,7 +49,7 @@ output_header = """//
 define_pat = re.compile(r"^char (peer[0|1]_\d+)\[\] = \{ \/\* (Packet \d+) \*\/$")
 
 # Matches a line in the middle of a packet or at the end, e.g.
-# 0x01, 0x00, 0x18, 0x00, 0x02, 0x00, 0x80, 0x00, 
+# 0x01, 0x00, 0x18, 0x00, 0x02, 0x00, 0x80, 0x00,
 # 0x08, 0x00, 0x0f, 0x00 };
 # No groups, use full match
 other_pat = re.compile(r"^((?:0x[0-9a-f]{2}, )*(?:0x[0-9a-f]{2}))(?: \};|, )$")
@@ -48,8 +57,10 @@ other_pat = re.compile(r"^((?:0x[0-9a-f]{2}, )*(?:0x[0-9a-f]{2}))(?: \};|, )$")
 # Used to seperate the two parties in the conversation (peer0 and peer1)
 var_sort_pat = re.compile(r"^peer0_\d+$")
 
-output_file.write(output_header)
-output_file.write("namespace {} {{\n\n".format(filename))
+cpp_file.write(OUTPUT_HEADER_CPP)
+cpp_file.write("namespace {} {{\n\n".format(filename))
+
+python_file.write(OUTPUT_HEADER_PYTHON)
 
 var_names_peer_0 = []
 var_names_peer_1 = []
@@ -60,7 +71,8 @@ while True:
         break
     m = define_pat.match(line)
     if m:
-        output_file.write("uint8_t {}[] = {{ // {}\n".format(m.group(1), m.group(2)))
+        cpp_file.write("uint8_t {}[] = {{ // {}\n".format(m.group(1), m.group(2)))
+        python_file.write("{} = bytes([ # {}\n".format(m.group(1), m.group(2)))
         var_sort_match = var_sort_pat.match(m.group(1))
         if var_sort_match:
             var_names_peer_0.append(m.group(1))
@@ -69,18 +81,31 @@ while True:
         continue
     m = other_pat.match(line)
     if m:
-        output_file.write(line)
+        cpp_file.write(line)
+        python_file.write(line.replace("};", "])"))
         continue
     print("Encountered unexpected line:\n{}".format(line))
-    exit()
+    sys.exit()
 
 for peer_name, var_names in [("peer0", var_names_peer_0), ("peer1", var_names_peer_1)]:
-    output_file.write("\n")
-    output_file.write("size_t {}_len = {};\n".format(peer_name, len(var_names)))
-    output_file.write("std::tuple<uint8_t*, size_t> {}[] = {{\n".format(peer_name))
-    for var_name in var_names:
-        output_file.write("\tstd::make_tuple({0}, sizeof({0})),\n".format(var_name))
-    output_file.write("};\n")
+    cpp_file.write("\n")
+    cpp_file.write("size_t {}_len = {};\n".format(peer_name, len(var_names)))
+    cpp_file.write("std::tuple<uint8_t*, size_t> {}[] = {{\n".format(peer_name))
 
-output_file.write("\n")
-output_file.write("}} // namespace {}\n".format(filename))
+    python_file.write("\n")
+    python_file.write("{} = [\n\t".format(peer_name))
+
+    for var_name in var_names:
+        cpp_file.write("\tstd::make_tuple({0}, sizeof({0})),\n".format(var_name))
+    cpp_file.write("};\n")
+
+    for i, var_name in enumerate(var_names):
+        python_file.write(var_name)
+        if i + 1 < len(var_names):
+            python_file.write(",\t")
+            if (i + 1) % 10 == 0:
+                python_file.write("\n\t")
+    python_file.write("\n]\n")
+
+cpp_file.write("\n")
+cpp_file.write("}} // namespace {}\n".format(filename))