coverage-badge 0.1.0

Generate shields.io-style SVG badges for test coverage percentages
Documentation 
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use crate::color::coverage_color;

/// Formats the percentage for display.
/// Shows decimal only if it's not a whole number.
fn format_percentage(percentage: f64) -> String {
    if percentage.fract() == 0.0 {
        format!("{}%", percentage as i64)
    } else {
        format!("{:.1}%", percentage)
    }
}

/// Generates an SVG badge for the given coverage percentage.
pub fn generate_badge(percentage: f64) -> String {
    let color = coverage_color(percentage);
    let percentage_text = format_percentage(percentage);

    // Approximate width calculation (shields.io style)
    // Label "coverage" is ~52px, percentage varies
    let label_width = 60;
    let value_width = 10 + (percentage_text.len() as i32 * 7);
    let total_width = label_width + value_width;
    let label_x = label_width / 2;
    let value_x = label_width + (value_width / 2);

    format!(
        "<svg xmlns=\"http://www.w3.org/2000/svg\" width=\"{}\" height=\"20\">
  <linearGradient id=\"smooth\" x2=\"0\" y2=\"100%\">
    <stop offset=\"0\" stop-color=\"#bbb\" stop-opacity=\".1\"/>
    <stop offset=\"1\" stop-opacity=\".1\"/>
  </linearGradient>
  <clipPath id=\"round\">
    <rect width=\"{}\" height=\"20\" rx=\"3\" fill=\"#fff\"/>
  </clipPath>
  <g clip-path=\"url(#round)\">
    <rect width=\"{}\" height=\"20\" fill=\"#555\"/>
    <rect x=\"{}\" width=\"{}\" height=\"20\" fill=\"{}\"/>
    <rect width=\"{}\" height=\"20\" fill=\"url(#smooth)\"/>
  </g>
  <g fill=\"#fff\" text-anchor=\"middle\" font-family=\"DejaVu Sans,Verdana,Geneva,sans-serif\" font-size=\"11\">
    <text x=\"{}\" y=\"15\" fill=\"#010101\" fill-opacity=\".3\">coverage</text>
    <text x=\"{}\" y=\"14\">coverage</text>
    <text x=\"{}\" y=\"15\" fill=\"#010101\" fill-opacity=\".3\">{}</text>
    <text x=\"{}\" y=\"14\">{}</text>
  </g>
</svg>",
        total_width,
        total_width,
        label_width,
        label_width,
        value_width,
        color,
        total_width,
        label_x,
        label_x,
        value_x,
        percentage_text,
        value_x,
        percentage_text
    )
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_badge_contains_coverage_label() {
        let svg = generate_badge(85.0);
        assert!(svg.contains("coverage"), "Badge should contain 'coverage' label");
    }

    #[test]
    fn test_badge_contains_percentage() {
        let svg = generate_badge(85.0);
        assert!(svg.contains("85%"), "Badge should contain percentage value");
    }

    #[test]
    fn test_badge_contains_correct_color() {
        let svg = generate_badge(85.0);
        assert!(svg.contains("#4c1"), "85% coverage should use green color");

        let svg_low = generate_badge(30.0);
        assert!(svg_low.contains("#e05d44"), "30% coverage should use red color");
    }

    #[test]
    fn test_badge_is_valid_svg() {
        let svg = generate_badge(50.0);
        assert!(svg.starts_with("<svg"), "Should start with <svg");
        assert!(svg.ends_with("</svg>"), "Should end with </svg>");
    }

    #[test]
    fn test_percentage_formatting_whole_number() {
        let svg = generate_badge(85.0);
        assert!(svg.contains("85%"));
        assert!(!svg.contains("85.0%"));
    }

    #[test]
    fn test_percentage_formatting_decimal() {
        let svg = generate_badge(85.5);
        assert!(svg.contains("85.5%"));
    }
}