crc32_test.cc File Reference

#include "catch2/catch.hpp"
#include "cetlib/crc32.h"
#include <string>
#include "CRC32Calculator.h"

Go to the source code of this file.

Functions
	SCENARIO ("We can produce CRC32 checksums accurately")

Function Documentation

SCENARIO

(

"We can produce CRC32 checksums accurately"

)

Definition at line 52 of file crc32_test.cc.

{
  crc32 crc;

  GIVEN("We have a short string")
  {
    WHEN("We create CRC32 digests in two different ways")
    {
      crc << TESTA;
      cet::CRC32Calculator const refMaker(TESTA);

      auto const digest = crc.digest();
      auto const ref = refMaker.checksum();

      THEN("The checksums compare equal") { CHECK(digest == ref); }
    }
  }

  GIVEN("We have a longer string")
  {
    WHEN("We create CRC32 digests in two different ways")
    {
      crc << TESTB;
      cet::CRC32Calculator const refMaker(TESTB);

      auto const digest = crc.digest();
      auto const ref = refMaker.checksum();

      THEN("The checksums compare equal") { CHECK(digest == ref); }
    }
  }

  GIVEN("We have a *much* longer string")
  {
    WHEN("We create CRC32 digests in two different ways")
    {
      crc << TESTC;
      cet::CRC32Calculator const refMaker(TESTC);

      auto const digest = crc.digest();
      auto const ref = refMaker.checksum();

      THEN("The checksums compare equal") { CHECK(digest == ref); }
    }
  }

  GIVEN("We have a string with a known, externally calculated CRC32 checksum")
  {
    WHEN("We create CRC32 digests in two different ways")
    {
      auto const testString = "type_label_instance"s;
      auto const process_suffix = "_process"s;
      auto const knownResult = 1215348599u;

      crc << (testString + process_suffix);
      cet::CRC32Calculator const refMaker(testString + process_suffix);

      auto const digest = crc.digest();
      auto const ref = refMaker.checksum();

      THEN("All three checksums compare equal")
      {
        CHECK(digest == knownResult);
        CHECK(digest == ref);
      }
      WHEN("We insert more text before calculating a digest")
      {
        crc32 crc_insert(testString);
        crc_insert << process_suffix;

        THEN("We get the same answer")
        {
          CHECK(crc_insert.digest() == knownResult);
        }
      }
    }
  }

  GIVEN("We have an empty string")
  {
    WHEN("We calculate its CRC32 checksum")
    {
      crc << "";

      THEN("It should be 0") { CHECK(crc.digest() == 0); }
    }
  }
}