"""
Tests for exception hierarchy — catch patterns, attributes.

Demonstrates: TDD (Interview Topic 8) — testing exception design.
"""

import pytest

from core.chunker.exceptions import (
    ChunkChecksumError,
    ChunkError,
    ChunkReadError,
    PipelineError,
    ProcessingError,
    ProcessorFailureError,
    ProcessorTimeoutError,
    ReassemblyError,
)


class TestExceptionHierarchy:
    """Verify the exception class hierarchy and catch patterns."""

    def test_pipeline_error_is_base(self):
        """All chunker exceptions inherit from PipelineError."""
        assert issubclass(ChunkError, PipelineError)
        assert issubclass(ProcessingError, PipelineError)
        assert issubclass(ReassemblyError, PipelineError)

    def test_chunk_error_subtypes(self):
        """ChunkReadError and ChunkChecksumError are ChunkErrors."""
        assert issubclass(ChunkReadError, ChunkError)
        assert issubclass(ChunkChecksumError, ChunkError)

    def test_processing_error_subtypes(self):
        """ProcessorTimeoutError and ProcessorFailureError are ProcessingErrors."""
        assert issubclass(ProcessorTimeoutError, ProcessingError)
        assert issubclass(ProcessorFailureError, ProcessingError)

    def test_catch_pipeline_error_catches_all(self):
        """Catching PipelineError catches any subtype."""
        with pytest.raises(PipelineError):
            raise ChunkReadError("test")

        with pytest.raises(PipelineError):
            raise ReassemblyError("test")

    def test_checksum_error_attributes(self):
        """ChunkChecksumError carries sequence, expected, actual."""
        err = ChunkChecksumError(sequence=5, expected="aaa", actual="bbb")
        assert err.sequence == 5
        assert err.expected == "aaa"
        assert err.actual == "bbb"
        assert "5" in str(err)

    def test_timeout_error_attributes(self):
        """ProcessorTimeoutError carries sequence and timeout."""
        err = ProcessorTimeoutError(sequence=3, timeout=30.0)
        assert err.sequence == 3
        assert err.timeout == 30.0

    def test_failure_error_attributes(self):
        """ProcessorFailureError carries sequence, retries, original error."""
        original = RuntimeError("boom")
        err = ProcessorFailureError(sequence=1, retries=3, original_error=original)
        assert err.sequence == 1
        assert err.retries == 3
        assert err.original_error is original
        assert "boom" in str(err)