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# frozen_string_literal: true
require 'spec_helper'
RSpec.describe Banzai::Filter::MathFilter, feature_category: :team_planning do
using RSpec::Parameterized::TableSyntax
include FilterSpecHelper
shared_examples 'inline math' do
it 'removes surrounding dollar signs and adds class code, math and js-render-math' do
doc = pipeline_filter(text)
expected = result_template.gsub('<math>', '<code data-math-style="inline" class="code math js-render-math">')
expected.gsub!('</math>', '</code>')
expect(doc.to_s).to eq expected
end
end
shared_examples 'display math' do
let_it_be(:template_prefix_with_pre) { '<pre data-canonical-lang="math" data-math-style="display" class="js-render-math"><code>' }
let_it_be(:template_prefix_with_code) { '<code data-math-style="display" class="code math js-render-math">' }
let(:use_pre_tags) { false }
it 'removes surrounding dollar signs and adds class code, math and js-render-math' do
doc = pipeline_filter(text)
template_prefix = use_pre_tags ? template_prefix_with_pre : template_prefix_with_code
template_suffix = "</code>#{'</pre>' if use_pre_tags}"
expected = result_template.gsub('<math>', template_prefix)
expected.gsub!('</math>', template_suffix)
expect(doc.to_s).to eq expected
end
end
describe 'inline math using $...$ syntax' do
context 'with valid syntax' do
where(:text, :result_template) do
'$2+2$' | '<p><math>2+2</math></p>'
'$22+1$ and $22 + a^2$' | '<p><math>22+1</math> and <math>22 + a^2</math></p>'
'$22 and $2+2$' | '<p>$22 and <math>2+2</math></p>'
'$2+2$ $22 and flightjs/Flight$22 $2+2$' | '<p><math>2+2</math> $22 and flightjs/Flight$22 <math>2+2</math></p>'
'$1/2$ <b>test</b>' | '<p><math>1/2</math> <b>test</b></p>'
'$a!$' | '<p><math>a!</math></p>'
'$x$' | '<p><math>x</math></p>'
'$1+2\$$' | '<p><math>1+2\$</math></p>'
'$1+\$2$' | '<p><math>1+\$2</math></p>'
'$1+\%2$' | '<p><math>1+\%2</math></p>'
'$1+\#2$' | '<p><math>1+\#2</math></p>'
'$1+\&2$' | '<p><math>1+\&2</math></p>'
'$1+\{2$' | '<p><math>1+\{2</math></p>'
'$1+\}2$' | '<p><math>1+\}2</math></p>'
'$1+\_2$' | '<p><math>1+\_2</math></p>'
end
with_them do
it_behaves_like 'inline math'
end
end
end
describe 'inline math using $`...`$ syntax' do
context 'with valid syntax' do
where(:text, :result_template) do
'$`2+2`$' | '<p><math>2+2</math></p>'
'$`22+1`$ and $`22 + a^2`$' | '<p><math>22+1</math> and <math>22 + a^2</math></p>'
'$22 and $`2+2`$' | '<p>$22 and <math>2+2</math></p>'
'$`2+2`$ $22 and flightjs/Flight$22 $`2+2`$' | '<p><math>2+2</math> $22 and flightjs/Flight$22 <math>2+2</math></p>'
'test $$`2+2`$$ test' | '<p>test $<math>2+2</math>$ test</p>'
'$`1+\$2`$' | '<p><math>1+\$2</math></p>'
end
with_them do
it_behaves_like 'inline math'
end
end
end
describe 'inline display math using $$...$$ syntax' do
context 'with valid syntax' do
where(:text, :result_template) do
'$$2+2$$' | '<p><math>2+2</math></p>'
'$$ 2+2 $$' | '<p><math>2+2</math></p>'
'$$22+1$$ and $$22 + a^2$$' | '<p><math>22+1</math> and <math>22 + a^2</math></p>'
'$22 and $$2+2$$' | '<p>$22 and <math>2+2</math></p>'
'$$2+2$$ $22 and flightjs/Flight$22 $$2+2$$' | '<p><math>2+2</math> $22 and flightjs/Flight$22 <math>2+2</math></p>'
'flightjs/Flight$22 and $$a^2 + b^2 = c^2$$' | '<p>flightjs/Flight$22 and <math>a^2 + b^2 = c^2</math></p>'
'$$a!$$' | '<p><math>a!</math></p>'
'$$x$$' | '<p><math>x</math></p>'
'$$20,000 and $$30,000' | '<p><math>20,000 and</math>30,000</p>'
end
with_them do
it_behaves_like 'display math'
end
end
end
describe 'block display math using $$\n...\n$$ syntax' do
context 'with valid syntax' do
where(:text, :result_template) do
"$$\n2+2\n$$" | "<math>2+2\n</math>"
"$$ \n2+2\n$$" | "<math>2+2\n</math>"
"$$\n2+2\n3+4\n$$" | "<math>2+2\n3+4\n</math>"
end
with_them do
it_behaves_like 'display math' do
let(:use_pre_tags) { true }
end
end
end
context 'when it spans multiple lines' do
let(:math) do
<<~MATH
\\begin{align*}
\\Delta t \\frac{d(b_i, a_i)}{c} + \\Delta t_{b_i}
\\end{align*}
MATH
end
let(:text) { "$$\n#{math}$$" }
let(:result_template) { "<math>#{math}</math>" }
it_behaves_like 'display math' do
let(:use_pre_tags) { true }
end
end
context 'when it contains \\' do
let(:math) do
<<~MATH
E = mc^2 \\\\
E = \\$mc^2
MATH
end
let(:text) { "$$\n#{math}$$" }
let(:result_template) { "<math>#{math}</math>" }
it_behaves_like 'display math' do
let(:use_pre_tags) { true }
end
end
end
describe 'display math using ```math...``` syntax' do
it 'adds data-math-style display attribute to display math' do
doc = pipeline_filter("```math\n2+2\n```")
pre = doc.xpath('descendant-or-self::pre').first
expect(pre['data-math-style']).to eq 'display'
end
it 'adds js-render-math class to display math' do
doc = pipeline_filter("```math\n2+2\n```")
pre = doc.xpath('descendant-or-self::pre').first
expect(pre[:class]).to include("js-render-math")
end
it 'ignores code blocks that are not math' do
input = "```plaintext\n2+2\n```"
doc = pipeline_filter(input)
expect(doc.to_s).to eq "<pre data-canonical-lang=\"plaintext\"><code>2+2\n</code></pre>"
end
it 'requires the pre to contain both code and math' do
input = '<pre data-canonical-lang="math">something</pre>'
doc = pipeline_filter(input)
expect(doc.to_s).to eq input
end
end
describe 'unrecognized syntax' do
where(:text, :result) do
'`2+2`' | '<p><code>2+2</code></p>'
'test $`2+2` test' | '<p>test $<code>2+2</code> test</p>'
'test `2+2`$ test' | '<p>test <code>2+2</code>$ test</p>'
'$20,000 and $30,000' | '<p>$20,000 and $30,000</p>'
'$20,000 in $USD' | '<p>$20,000 in $USD</p>'
'$ a^2 $' | '<p>$ a^2 $</p>'
"test $$\n2+2\n$$" | "<p>test $$\n2+2\n$$</p>"
"$\n$" | "<p>$\n$</p>"
'$$$' | '<p>$$$</p>'
'`$1+2$`' | '<p><code>$1+2$</code></p>'
'`$$1+2$$`' | '<p><code>$$1+2$$</code></p>'
'`$\$1+2$$`' | '<p><code>$\$1+2$$</code></p>'
end
with_them do
it 'is ignored' do
expect(pipeline_filter(text).to_s).to eq result
end
end
end
it 'handles multiple styles in one text block' do
doc = pipeline_filter('$`2+2`$ + $3+3$ + $$4+4$$')
expect(doc.search('.js-render-math').count).to eq(3)
expect(doc.search('[data-math-style="inline"]').count).to eq(2)
expect(doc.search('[data-math-style="display"]').count).to eq(1)
end
context 'when limiting how many elements can be marked as math' do
subject { pipeline_filter('$`2+2`$ + $3+3$ + $$4+4$$') }
it 'enforces limits by default' do
stub_const('Banzai::Filter::MathFilter::RENDER_NODES_LIMIT', 2)
expect(subject.search('.js-render-math').count).to eq(2)
end
it 'does not limit when math_rendering_limits_enabled is false' do
stub_application_setting(math_rendering_limits_enabled: false)
stub_const('Banzai::Filter::MathFilter::RENDER_NODES_LIMIT', 2)
expect(subject.search('.js-render-math').count).to eq(3)
end
end
it 'protects against malicious backtracking' do
doc = pipeline_filter("$$#{' ' * 1_000_000}$")
expect do
Timeout.timeout(3.seconds) { filter(doc) }
end.not_to raise_error
end
def pipeline_filter(text)
context = { project: nil, no_sourcepos: true }
doc = Banzai::Pipeline::PreProcessPipeline.call(text, {})
doc = Banzai::Pipeline::PlainMarkdownPipeline.call(doc[:output], context)
doc = Banzai::Filter::CodeLanguageFilter.call(doc[:output], context, nil)
doc = Banzai::Filter::SanitizationFilter.call(doc, context, nil)
filter(doc)
end
end
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