block math test fixture

test/fixtures/default.txt

@@ -2,7 +2,14 @@
 Simple inline math
 .
 $1+1 = 2$
-
 .
 <p><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mn>1</mn><mo>+</mo><mn>1</mn><mo>=</mo><mn>2</mn></mrow><annotation encoding="application/x-tex">1+1 = 2</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="strut" style="height:0.64444em;"></span><span class="strut bottom" style="height:0.72777em;vertical-align:-0.08333em;"></span><span class="base textstyle uncramped"><span class="mord mathrm">1</span><span class="mbin">+</span><span class="mord mathrm">1</span><span class="mrel">=</span><span class="mord mathrm">2</span></span></span></span></p>
 .
+
+Simple block math
+.
+$$1+1 = 2$$
+.
+<span class="katex-display"><span class="katex"><span class="katex-mathml"><math><semantics><mrow><mn>1</mn><mo>+</mo><mn>1</mn><mo>=</mo><mn>2</mn></mrow><annotation encoding="application/x-tex">1+1 = 2
+</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="strut" style="height:0.64444em;"></span><span class="strut bottom" style="height:0.72777em;vertical-align:-0.08333em;"></span><span class="base displaystyle textstyle uncramped"><span class="mord mathrm">1</span><span class="mbin">+</span><span class="mord mathrm">1</span><span class="mrel">=</span><span class="mord mathrm">2</span></span></span></span></span>
+.