S003 Success Criteria

ID	Criterion
S003-SC-001	Given a Clover XML file with known statement counts, CoverageReader::read() produces per-file percentages that match round(100 * coveredstatements / statements, 2) for every <file> element.
S003-SC-002	Given a PHPUnit XML directory with known per-file <lines percent="..."> values, PhpUnitXmlCoverageReader::read() returns coverage values that match each file's percent attribute exactly.
S003-SC-003	Given a PHPUnit XML directory where specific lines are annotated with <covered by="TestClass::method"/>, the testsByFile map contains exactly the deduplicated set of test identifiers per file, and lineCoverage maps each line number to its correct list of test identifiers.
S003-SC-004	Given a coverage_xml config of ['coverage-xml', 'clover.xml', 'cobertura.xml'], format detection always selects PHPUnit XML when the directory exists with index.xml, and otherwise selects the first existing single-file coverage XML candidate. The result is deterministic regardless of filesystem ordering.
S003-SC-005	For every error condition (missing file, malformed XML, permission denied, missing index.xml), the reader returns an empty/null result without throwing exceptions or emitting PHP warnings to stderr.
S003-SC-006	Given a Cobertura XML file with known line-rate values, CoverageReader::read() and readGlobalCoverage() produce percentages that match round(line-rate * 100, 2).