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Testing Rich Text Segment Manipulation and Styling in Textualize/rich

A comprehensive test suite for the Segment class in the Rich library, validating text segment manipulation, styling, and rendering capabilities. The tests ensure proper handling of text segments with various styles, controls, and Unicode characters including emojis.

Test Coverage Overview

The test suite provides extensive coverage of the Segment class functionality in Rich.

Key areas tested include:
  • Text segment creation and manipulation
  • Style application and management
  • Line splitting and cropping
  • Unicode and emoji handling
  • Control sequence processing
  • Text alignment and formatting

Implementation Analysis

The testing approach uses pytest fixtures and parametrized tests for thorough validation.

Notable patterns include:
  • Systematic edge case testing for text manipulation
  • Comprehensive style and control handling verification
  • Complex Unicode character testing
  • Integration with Rich’s styling system

Technical Details

Testing infrastructure includes:
  • pytest framework for test organization
  • StringIO for console output capture
  • Rich’s internal styling and control systems
  • Custom assertions for segment validation
  • Unicode character handling utilities

Best Practices Demonstrated

The test suite exemplifies high-quality testing practices.

Notable examples include:
  • Comprehensive edge case coverage
  • Parametrized testing for multiple scenarios
  • Clear test organization and naming
  • Thorough validation of complex text operations
  • Integration test cases for real-world scenarios

textualize/rich

tests/test_segment.py

            
from io import StringIO

import pytest

from rich.cells import cell_len
from rich.segment import ControlType, Segment, SegmentLines, Segments
from rich.style import Style


def test_repr():
    assert repr(Segment("foo")) == "Segment('foo')"
    home = (ControlType.HOME, 0)
    assert (
        repr(Segment("foo", None, [home]))
        == "Segment('foo', None, [(<ControlType.HOME: 3>, 0)])"
    )


def test_line():
    assert Segment.line() == Segment("
")


def test_apply_style():
    segments = [Segment("foo"), Segment("bar", Style(bold=True))]
    assert Segment.apply_style(segments, None) is segments
    assert list(Segment.apply_style(segments, Style(italic=True))) == [
        Segment("foo", Style(italic=True)),
        Segment("bar", Style(italic=True, bold=True)),
    ]


def test_split_lines():
    lines = [Segment("Hello
World")]
    assert list(Segment.split_lines(lines)) == [[Segment("Hello")], [Segment("World")]]


def test_split_and_crop_lines():
    assert list(
        Segment.split_and_crop_lines([Segment("Hello
World!
"), Segment("foo")], 4)
    ) == [
        [Segment("Hell"), Segment("
", None)],
        [Segment("Worl"), Segment("
", None)],
        [Segment("foo"), Segment(" ")],
    ]


def test_adjust_line_length():
    line = [Segment("Hello", "foo")]
    assert Segment.adjust_line_length(line, 10, style="bar") == [
        Segment("Hello", "foo"),
        Segment("     ", "bar"),
    ]

    line = [Segment("H"), Segment("ello, World!")]
    assert Segment.adjust_line_length(line, 5) == [Segment("H"), Segment("ello")]

    line = [Segment("Hello")]
    assert Segment.adjust_line_length(line, 5) == line


def test_get_line_length():
    assert Segment.get_line_length([Segment("foo"), Segment("bar")]) == 6


def test_get_shape():
    assert Segment.get_shape([[Segment("Hello")]]) == (5, 1)
    assert Segment.get_shape([[Segment("Hello")], [Segment("World!")]]) == (6, 2)


def test_set_shape():
    assert Segment.set_shape([[Segment("Hello")]], 10) == [
        [Segment("Hello"), Segment("     ")]
    ]
    assert Segment.set_shape([[Segment("Hello")]], 10, 2) == [
        [Segment("Hello"), Segment("     ")],
        [Segment(" " * 10)],
    ]


def test_simplify():
    assert list(
        Segment.simplify([Segment("Hello"), Segment(" "), Segment("World!")])
    ) == [Segment("Hello World!")]
    assert list(
        Segment.simplify(
            [Segment("Hello", "red"), Segment(" ", "red"), Segment("World!", "blue")]
        )
    ) == [Segment("Hello ", "red"), Segment("World!", "blue")]
    assert list(Segment.simplify([])) == []


def test_filter_control():
    control_code = (ControlType.HOME, 0)
    segments = [Segment("foo"), Segment("bar", None, (control_code,))]
    assert list(Segment.filter_control(segments)) == [Segment("foo")]
    assert list(Segment.filter_control(segments, is_control=True)) == [
        Segment("bar", None, (control_code,))
    ]


def test_strip_styles():
    segments = [Segment("foo", Style(bold=True))]
    assert list(Segment.strip_styles(segments)) == [Segment("foo", None)]


def test_strip_links():
    segments = [Segment("foo", Style(bold=True, link="https://www.example.org"))]
    assert list(Segment.strip_links(segments)) == [Segment("foo", Style(bold=True))]


def test_remove_color():
    segments = [
        Segment("foo", Style(bold=True, color="red")),
        Segment("bar", None),
    ]
    assert list(Segment.remove_color(segments)) == [
        Segment("foo", Style(bold=True)),
        Segment("bar", None),
    ]


def test_is_control():
    assert Segment("foo", Style(bold=True)).is_control == False
    assert Segment("foo", Style(bold=True), []).is_control == True
    assert Segment("foo", Style(bold=True), [(ControlType.HOME, 0)]).is_control == True


def test_segments_renderable():
    segments = Segments([Segment("foo")])
    assert list(segments.__rich_console__(None, None)) == [Segment("foo")]

    segments = Segments([Segment("foo")], new_lines=True)
    assert list(segments.__rich_console__(None, None)) == [
        Segment("foo"),
        Segment.line(),
    ]


def test_divide():
    bold = Style(bold=True)
    italic = Style(italic=True)
    segments = [
        Segment("Hello", bold),
        Segment(" World!", italic),
    ]

    assert list(Segment.divide(segments, [])) == []
    assert list(Segment.divide([], [1])) == [[]]

    assert list(Segment.divide(segments, [1])) == [[Segment("H", bold)]]

    assert list(Segment.divide(segments, [1, 2])) == [
        [Segment("H", bold)],
        [Segment("e", bold)],
    ]

    assert list(Segment.divide(segments, [1, 2, 12])) == [
        [Segment("H", bold)],
        [Segment("e", bold)],
        [Segment("llo", bold), Segment(" World!", italic)],
    ]

    assert list(Segment.divide(segments, [4, 20])) == [
        [Segment("Hell", bold)],
        [Segment("o", bold), Segment(" World!", italic)],
    ]


# https://github.com/textualize/rich/issues/1755
def test_divide_complex():
    MAP = (
        "[on orange4]          [on green]XX[on orange4]          
"
        "                        
"
        "                        
"
        "                        
"
        "              [bright_red on black]Y[on orange4]        
"
        "[on green]X[on orange4]                  [on green]X[on orange4]  
"
        " [on green]X[on orange4]                   [on green]X
"
        "[on orange4]                        
"
        "          [on green]XX[on orange4]          
"
    )
    from rich.console import Console
    from rich.text import Text

    text = Text.from_markup(MAP)
    console = Console(
        color_system="truecolor", width=30, force_terminal=True, file=StringIO()
    )
    console.print(text)
    result = console.file.getvalue()

    print(repr(result))
    expected = "\x1b[48;5;94m          \x1b[0m\x1b[42mXX\x1b[0m\x1b[48;5;94m          \x1b[0m
\x1b[48;5;94m                        \x1b[0m
\x1b[48;5;94m                        \x1b[0m
\x1b[48;5;94m                        \x1b[0m
\x1b[48;5;94m              \x1b[0m\x1b[91;40mY\x1b[0m\x1b[91;48;5;94m        \x1b[0m
\x1b[91;42mX\x1b[0m\x1b[91;48;5;94m                  \x1b[0m\x1b[91;42mX\x1b[0m\x1b[91;48;5;94m  \x1b[0m
\x1b[91;48;5;94m \x1b[0m\x1b[91;42mX\x1b[0m\x1b[91;48;5;94m                   \x1b[0m\x1b[91;42mX\x1b[0m
\x1b[91;48;5;94m                        \x1b[0m
\x1b[91;48;5;94m          \x1b[0m\x1b[91;42mXX\x1b[0m\x1b[91;48;5;94m          \x1b[0m

"
    assert result == expected


def test_divide_emoji():
    bold = Style(bold=True)
    italic = Style(italic=True)
    segments = [
        Segment("Hello", bold),
        Segment("💩💩💩", italic),
    ]

    assert list(Segment.divide(segments, [7])) == [
        [Segment("Hello", bold), Segment("💩", italic)],
    ]
    assert list(Segment.divide(segments, [8])) == [
        [Segment("Hello", bold), Segment("💩 ", italic)],
    ]
    assert list(Segment.divide(segments, [9])) == [
        [Segment("Hello", bold), Segment("💩💩", italic)],
    ]
    assert list(Segment.divide(segments, [8, 11])) == [
        [Segment("Hello", bold), Segment("💩 ", italic)],
        [Segment(" 💩", italic)],
    ]
    assert list(Segment.divide(segments, [9, 11])) == [
        [Segment("Hello", bold), Segment("💩💩", italic)],
        [Segment("💩", italic)],
    ]


def test_divide_edge():
    segments = [Segment("foo"), Segment("bar"), Segment("baz")]
    result = list(Segment.divide(segments, [1, 3, 9]))
    print(result)
    assert result == [
        [Segment("f")],
        [Segment("oo")],
        [Segment("bar"), Segment("baz")],
    ]


def test_divide_edge_2():
    segments = [
        Segment("╭─"),
        Segment(
            "────── Placeholder ───────",
        ),
        Segment(
            "─╮",
        ),
    ]
    result = list(Segment.divide(segments, [30, 60]))
    expected = [segments, []]
    print(repr(result))
    assert result == expected


@pytest.mark.parametrize(
    "text,split,result",
    [
        ("XX", 4, (Segment("XX"), Segment(""))),
        ("X", 1, (Segment("X"), Segment(""))),
        ("💩", 1, (Segment(" "), Segment(" "))),
        ("XY", 1, (Segment("X"), Segment("Y"))),
        ("💩X", 1, (Segment(" "), Segment(" X"))),
        ("💩💩", 1, (Segment(" "), Segment(" 💩"))),
        ("X💩Y", 2, (Segment("X "), Segment(" Y"))),
        ("X💩YZ", 2, (Segment("X "), Segment(" YZ"))),
        ("X💩💩Z", 2, (Segment("X "), Segment(" 💩Z"))),
        ("X💩💩Z", 3, (Segment("X💩"), Segment("💩Z"))),
        ("X💩💩Z", 4, (Segment("X💩 "), Segment(" Z"))),
        ("X💩💩Z", 5, (Segment("X💩💩"), Segment("Z"))),
        ("X💩💩Z", 6, (Segment("X💩💩Z"), Segment(""))),
        ("XYZABC💩💩", 6, (Segment("XYZABC"), Segment("💩💩"))),
        ("XYZABC💩💩", 7, (Segment("XYZABC "), Segment(" 💩"))),
        ("XYZABC💩💩", 8, (Segment("XYZABC💩"), Segment("💩"))),
        ("XYZABC💩💩", 9, (Segment("XYZABC💩 "), Segment(" "))),
        ("XYZABC💩💩", 10, (Segment("XYZABC💩💩"), Segment(""))),
        ("💩💩💩💩💩", 3, (Segment("💩 "), Segment(" 💩💩💩"))),
        ("💩💩💩💩💩", 4, (Segment("💩💩"), Segment("💩💩💩"))),
        ("💩X💩Y💩Z💩A💩", 4, (Segment("💩X "), Segment(" Y💩Z💩A💩"))),
        ("XYZABC", 4, (Segment("XYZA"), Segment("BC"))),
        ("XYZABC", 5, (Segment("XYZAB"), Segment("C"))),
        (
            "a1あ１１bcdaef",
            9,
            (Segment("a1あ１１b"), Segment("cdaef")),
        ),
    ],
)
def test_split_cells_emoji(text, split, result):
    assert Segment(text).split_cells(split) == result


@pytest.mark.parametrize(
    "segment",
    [
        Segment("早乙女リリエル (CV: 徳井青）"),
        Segment("メイド・イン・きゅんクチュアリ☆    "),
        Segment("TVアニメ「メルクストーリア -無気力少年と瓶の中の少女-」 主題歌CD"),
        Segment("南無阿弥JKうらめしや?！     "),
        Segment("メルク (CV: 水瀬いのり)     "),
        Segment(" メルク (CV: 水瀬いのり)     "),
        Segment("  メルク (CV: 水瀬いのり)     "),
        Segment("  メルク (CV: 水瀬いのり)      "),
    ],
)
def test_split_cells_mixed(segment: Segment) -> None:
    """Check that split cells splits on cell positions."""
    # Caused https://github.com/Textualize/textual/issues/4996 in Textual

    for position in range(0, segment.cell_length + 1):
        left, right = Segment.split_cells(segment, position)
        assert all(
            cell_len(c) > 0 for c in segment.text
        )  # Sanity check there aren't any sneaky control codes
        assert cell_len(left.text) == position
        assert cell_len(right.text) == segment.cell_length - position


def test_split_cells_doubles() -> None:
    """Check that split cells splits on cell positions with all double width characters."""
    test = Segment("早" * 20)
    for position in range(1, test.cell_length):
        left, right = Segment.split_cells(test, position)
        assert cell_len(left.text) == position
        assert cell_len(right.text) == test.cell_length - position


def test_split_cells_single() -> None:
    """Check that split cells splits on cell positions with all single width characters."""
    test = Segment("A" * 20)
    for position in range(1, test.cell_length):
        left, right = Segment.split_cells(test, position)
        assert cell_len(left.text) == position
        assert cell_len(right.text) == test.cell_length - position


def test_segment_lines_renderable():
    lines = [[Segment("hello"), Segment(" "), Segment("world")], [Segment("foo")]]
    segment_lines = SegmentLines(lines)
    assert list(segment_lines.__rich_console__(None, None)) == [
        Segment("hello"),
        Segment(" "),
        Segment("world"),
        Segment("foo"),
    ]

    segment_lines = SegmentLines(lines, new_lines=True)
    assert list(segment_lines.__rich_console__(None, None)) == [
        Segment("hello"),
        Segment(" "),
        Segment("world"),
        Segment("
"),
        Segment("foo"),
        Segment("
"),
    ]


def test_align_top():
    lines = [[Segment("X")]]
    assert Segment.align_top(lines, 3, 1, Style()) == lines
    assert Segment.align_top(lines, 3, 3, Style()) == [
        [Segment("X")],
        [Segment("   ", Style())],
        [Segment("   ", Style())],
    ]


def test_align_middle():
    lines = [[Segment("X")]]
    assert Segment.align_middle(lines, 3, 1, Style()) == lines
    assert Segment.align_middle(lines, 3, 3, Style()) == [
        [Segment("   ", Style())],
        [Segment("X")],
        [Segment("   ", Style())],
    ]


def test_align_bottom():
    lines = [[Segment("X")]]
    assert Segment.align_bottom(lines, 3, 1, Style()) == lines
    assert Segment.align_bottom(lines, 3, 3, Style()) == [
        [Segment("   ", Style())],
        [Segment("   ", Style())],
        [Segment("X")],
    ]