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Testing DBC File Operations in openpilot Cabana Tool

This test suite validates the DBC (Database CAN) file handling functionality in the Cabana tool of openpilot. It focuses on testing DBC file parsing, generation, and manipulation capabilities essential for CAN bus message interpretation.

Test Coverage Overview

The test suite provides comprehensive coverage of DBC file operations:

DBC file generation and content preservation
Comment handling and ordering verification
Header preservation and format validation
Complex message parsing including multiplexed signals
Support for escaped characters and multi-line comments

Implementation Analysis

The testing approach employs Catch2 framework for C++ unit testing, focusing on verification of DBC file structure and content integrity. Tests utilize fixture-based setup with both static test files and dynamically generated content to validate parsing and generation functionality.

Key patterns include comparison-based verification and exhaustive attribute checking for CAN messages and signals.

Technical Details

Testing infrastructure includes:

Catch2 testing framework
Qt framework for file operations
Custom DBCFile class implementation
Test data from OpenDBC repository
Structured test cases for different DBC file aspects

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Systematic validation of file generation and parsing
Comprehensive error handling verification
Edge case coverage for special characters and formatting
Modular test organization with focused test cases
Real-world validation using OpenDBC files

commaai/openpilot

tools/cabana/tests/test_cabana.cc

            

#undef INFO
#include <QDir>

#include "catch2/catch.hpp"
#include "tools/cabana/dbc/dbcmanager.h"

const std::string TEST_RLOG_URL = "https://commadataci.blob.core.windows.net/openpilotci/0c94aa1e1296d7c6/2021-05-05--19-48-37/0/rlog.bz2";

TEST_CASE("DBCFile::generateDBC") {
  QString fn = QString("%1/%2.dbc").arg(OPENDBC_FILE_PATH, "tesla_can");
  DBCFile dbc_origin(fn);
  DBCFile dbc_from_generated("", dbc_origin.generateDBC());

  REQUIRE(dbc_origin.getMessages().size() == dbc_from_generated.getMessages().size());
  auto &msgs = dbc_origin.getMessages();
  auto &new_msgs = dbc_from_generated.getMessages();
  for (auto &[id, m] : msgs) {
    auto &new_m = new_msgs.at(id);
    REQUIRE(m.name == new_m.name);
    REQUIRE(m.size == new_m.size);
    REQUIRE(m.getSignals().size() == new_m.getSignals().size());
    auto sigs = m.getSignals();
    auto new_sigs = new_m.getSignals();
    for (int i = 0; i < sigs.size(); ++i) {
      REQUIRE(*sigs[i] == *new_sigs[i]);
    }
  }
}

TEST_CASE("DBCFile::generateDBC - comment order") {
  // Ensure that message comments are followed by signal comments and in the correct order
  auto content = R"(BO_ 160 message_1: 8 EON
 SG_ signal_1 : 0|12@1+ (1,0) [0|4095] "unit" XXX

BO_ 162 message_2: 8 EON
 SG_ signal_2 : 0|12@1+ (1,0) [0|4095] "unit" XXX

CM_ BO_ 160 "message comment";
CM_ SG_ 160 signal_1 "signal comment";
CM_ BO_ 162 "message comment";
CM_ SG_ 162 signal_2 "signal comment";
)";
  DBCFile dbc("", content);
  REQUIRE(dbc.generateDBC() == content);
}

TEST_CASE("DBCFile::generateDBC -- preserve original header") {
  QString content = R"(VERSION "1.0"

NS_ :
 CM_

BS_:

BU_: EON

BO_ 160 message_1: 8 EON
 SG_ signal_1 : 0|12@1+ (1,0) [0|4095] "unit" XXX

CM_ BO_ 160 "message comment";
CM_ SG_ 160 signal_1 "signal comment";
)";
  DBCFile dbc("", content);
  REQUIRE(dbc.generateDBC() == content);
}

TEST_CASE("DBCFile::generateDBC - escaped quotes") {
  QString content = R"(BO_ 160 message_1: 8 EON
 SG_ signal_1 : 0|12@1+ (1,0) [0|4095] "unit" XXX

CM_ BO_ 160 "message comment with \"escaped quotes\"";
CM_ SG_ 160 signal_1 "signal comment with \"escaped quotes\"";
)";
  DBCFile dbc("", content);
  REQUIRE(dbc.generateDBC() == content);
}

TEST_CASE("parse_dbc") {
  QString content = R"(
BO_ 160 message_1: 8 EON
  SG_ signal_1 : 0|12@1+ (1,0) [0|4095] "unit"  XXX
  SG_ signal_2 : 12|1@1+ (1.0,0.0) [0.0|1] ""  XXX

BO_ 162 message_1: 8 XXX
  SG_ signal_1 M : 0|12@1+ (1,0) [0|4095] "unit" XXX
  SG_ signal_2 M4 : 12|1@1+ (1.0,0.0) [0.0|1] "" XXX

VAL_ 160 signal_1 0 "disabled" 1.2 "initializing" 2 "fault";

CM_ BO_ 160 "message comment" ;
CM_ SG_ 160 signal_1 "signal comment";
CM_ SG_ 160 signal_2 "multiple line comment 
1
2
";

CM_ BO_ 162 "message comment with \"escaped quotes\"";
CM_ SG_ 162 signal_1 "signal comment with \"escaped quotes\"";
)";

  DBCFile file("", content);
  auto msg = file.msg(160);
  REQUIRE(msg != nullptr);
  REQUIRE(msg->name == "message_1");
  REQUIRE(msg->size == 8);
  REQUIRE(msg->comment == "message comment");
  REQUIRE(msg->sigs.size() == 2);
  REQUIRE(msg->transmitter == "EON");
  REQUIRE(file.msg("message_1") != nullptr);

  auto sig_1 = msg->sigs[0];
  REQUIRE(sig_1->name == "signal_1");
  REQUIRE(sig_1->start_bit == 0);
  REQUIRE(sig_1->size == 12);
  REQUIRE(sig_1->min == 0);
  REQUIRE(sig_1->max == 4095);
  REQUIRE(sig_1->unit == "unit");
  REQUIRE(sig_1->comment == "signal comment");
  REQUIRE(sig_1->receiver_name == "XXX");
  REQUIRE(sig_1->val_desc.size() == 3);
  REQUIRE(sig_1->val_desc[0] == std::pair<double, QString>{0, "disabled"});
  REQUIRE(sig_1->val_desc[1] == std::pair<double, QString>{1.2, "initializing"});
  REQUIRE(sig_1->val_desc[2] == std::pair<double, QString>{2, "fault"});

  auto &sig_2 = msg->sigs[1];
  REQUIRE(sig_2->comment == "multiple line comment 
1
2");

  // multiplexed signals
  msg = file.msg(162);
  REQUIRE(msg != nullptr);
  REQUIRE(msg->sigs.size() == 2);
  REQUIRE(msg->sigs[0]->type == cabana::Signal::Type::Multiplexor);
  REQUIRE(msg->sigs[1]->type == cabana::Signal::Type::Multiplexed);
  REQUIRE(msg->sigs[1]->multiplex_value == 4);
  REQUIRE(msg->sigs[1]->start_bit == 12);
  REQUIRE(msg->sigs[1]->size == 1);
  REQUIRE(msg->sigs[1]->receiver_name == "XXX");

  // escaped quotes
  REQUIRE(msg->comment == "message comment with \"escaped quotes\"");
  REQUIRE(msg->sigs[0]->comment == "signal comment with \"escaped quotes\"");
}

TEST_CASE("parse_opendbc") {
  QDir dir(OPENDBC_FILE_PATH);
  QStringList errors;
  for (auto fn : dir.entryList({"*.dbc"}, QDir::Files, QDir::Name)) {
    try {
      auto dbc = DBCFile(dir.filePath(fn));
    } catch (std::exception &e) {
      errors.push_back(e.what());
    }
  }
  INFO(errors.join("
").toStdString());
  REQUIRE(errors.empty());
}