Add more tests for attention

1 files changed, 877 insertions, 0 deletions

diff --git a/tests/attention.rs b/tests/attention.rs
new file mode 100644
index 0000000..c7d4135
--- /dev/null
+++ b/tests/attention.rs
@@ -0,0 +1,877 @@
+extern crate micromark;
+use micromark::{micromark, micromark_with_options, Options};
+
+const DANGER: &Options = &Options {
+    allow_dangerous_html: true,
+    allow_dangerous_protocol: true,
+    default_line_ending: None,
+};
+
+#[test]
+fn attention() {
+    // Rule 1.
+    assert_eq!(
+        micromark("*foo bar*"),
+        "<p><em>foo bar</em></p>",
+        "should support emphasis w/ `*`"
+    );
+
+    assert_eq!(
+        micromark("a * foo bar*"),
+        "<p>a * foo bar*</p>",
+        "should not support emphasis if the opening is not left flanking (1)"
+    );
+
+    assert_eq!(
+        micromark("a*\"foo\"*"),
+        "<p>a*&quot;foo&quot;*</p>",
+        "should not support emphasis if the opening is not left flanking (2b)"
+    );
+
+    assert_eq!(
+        micromark("* a *"),
+        "<p>* a *</p>",
+        "should not support emphasis unicode whitespace either"
+    );
+
+    assert_eq!(
+        micromark("foo*bar*"),
+        "<p>foo<em>bar</em></p>",
+        "should support intraword emphasis w/ `*` (1)"
+    );
+
+    assert_eq!(
+        micromark("5*6*78"),
+        "<p>5<em>6</em>78</p>",
+        "should support intraword emphasis w/ `*` (2)"
+    );
+
+    // Rule 2.
+    assert_eq!(
+        micromark("_foo bar_"),
+        "<p><em>foo bar</em></p>",
+        "should support emphasis w/ `_`"
+    );
+
+    assert_eq!(
+        micromark("_ foo bar_"),
+        "<p>_ foo bar_</p>",
+        "should not support emphasis if the opening is followed by whitespace"
+    );
+
+    assert_eq!(
+        micromark("a_\"foo\"_"),
+        "<p>a_&quot;foo&quot;_</p>",
+        "should not support emphasis if the opening is preceded by something else and followed by punctuation"
+    );
+
+    assert_eq!(
+        micromark("foo_bar_"),
+        "<p>foo_bar_</p>",
+        "should not support intraword emphasis (1)"
+    );
+
+    assert_eq!(
+        micromark("5_6_78"),
+        "<p>5_6_78</p>",
+        "should not support intraword emphasis (2)"
+    );
+
+    assert_eq!(
+        micromark("пристаням_стремятся_"),
+        "<p>пристаням_стремятся_</p>",
+        "should not support intraword emphasis (3)"
+    );
+
+    assert_eq!(
+       micromark("aa_\"bb\"_cc"),
+        "<p>aa_&quot;bb&quot;_cc</p>",
+        "should not support emphasis if the opening is right flanking and the closing is left flanking"
+    );
+
+    assert_eq!(
+        micromark("foo-_(bar)_"),
+        "<p>foo-<em>(bar)</em></p>",
+        "should support emphasis if the opening is both left and right flanking, if it’s preceded by punctuation"
+    );
+
+    // Rule 3.
+    assert_eq!(
+        micromark("_foo*"),
+        "<p>_foo*</p>",
+        "should not support emphasis if opening and closing markers don’t match"
+    );
+
+    assert_eq!(
+        micromark("*foo bar *"),
+        "<p>*foo bar *</p>",
+        "should not support emphasis w/ `*` if the closing markers are preceded by whitespace"
+    );
+
+    assert_eq!(
+        micromark("*foo bar\n*"),
+        "<p>*foo bar\n*</p>",
+        "should not support emphasis w/ `*` if the closing markers are preceded by a line break (also whitespace)"
+    );
+
+    assert_eq!(
+        micromark("*(*foo)"),
+        "<p>*(*foo)</p>",
+        "should not support emphasis w/ `*` if the closing markers are not right flanking"
+    );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("*(*foo*)*"),
+    //     "<p><em>(<em>foo</em>)</em></p>",
+    //     "should support nested emphasis"
+    // );
+
+    // Rule 4.
+    assert_eq!(
+        micromark("_foo bar _"),
+        "<p>_foo bar _</p>",
+        "should not support emphasis if the closing `_` is preceded by whitespace"
+    );
+
+    assert_eq!(
+        micromark("_(_foo)"),
+        "<p>_(_foo)</p>",
+        "should not support emphasis w/ `_` if the closing markers are not right flanking"
+    );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("_(_foo_)_"),
+    //     "<p><em>(<em>foo</em>)</em></p>",
+    //     "should support nested emphasis w/ `_`"
+    // );
+
+    assert_eq!(
+        micromark("_foo_bar"),
+        "<p>_foo_bar</p>",
+        "should not support intraword emphasis w/ `_` (1)"
+    );
+
+    assert_eq!(
+        micromark("_пристаням_стремятся"),
+        "<p>_пристаням_стремятся</p>",
+        "should not support intraword emphasis w/ `_` (2)"
+    );
+
+    assert_eq!(
+        micromark("_foo_bar_baz_"),
+        "<p><em>foo_bar_baz</em></p>",
+        "should not support intraword emphasis w/ `_` (3)"
+    );
+
+    assert_eq!(
+        micromark("_(bar)_."),
+        "<p><em>(bar)</em>.</p>",
+        "should support emphasis if the opening is both left and right flanking, if it’s followed by punctuation"
+    );
+
+    // Rule 5.
+    assert_eq!(
+        micromark("**foo bar**"),
+        "<p><strong>foo bar</strong></p>",
+        "should support strong emphasis"
+    );
+
+    assert_eq!(
+        micromark("** foo bar**"),
+        "<p>** foo bar**</p>",
+        "should not support strong emphasis if the opening is followed by whitespace"
+    );
+
+    assert_eq!(
+    micromark("a**\"foo\"**"),
+    "<p>a**&quot;foo&quot;**</p>",
+    "should not support strong emphasis if the opening is preceded by something else and followed by punctuation"
+  );
+
+    assert_eq!(
+        micromark("foo**bar**"),
+        "<p>foo<strong>bar</strong></p>",
+        "should support strong intraword emphasis"
+    );
+
+    // Rule 6.
+    assert_eq!(
+        micromark("__foo bar__"),
+        "<p><strong>foo bar</strong></p>",
+        "should support strong emphasis w/ `_`"
+    );
+
+    assert_eq!(
+        micromark("__ foo bar__"),
+        "<p>__ foo bar__</p>",
+        "should not support strong emphasis if the opening is followed by whitespace"
+    );
+
+    assert_eq!(
+        micromark("__\nfoo bar__"),
+        "<p>__\nfoo bar__</p>",
+        "should not support strong emphasis if the opening is followed by a line ending (also whitespace)"
+    );
+
+    assert_eq!(
+        micromark("a__\"foo\"__"),
+        "<p>a__&quot;foo&quot;__</p>",
+        "should not support strong emphasis if the opening is preceded by something else and followed by punctuation"
+    );
+
+    assert_eq!(
+        micromark("foo__bar__"),
+        "<p>foo__bar__</p>",
+        "should not support strong intraword emphasis w/ `_` (1)"
+    );
+
+    assert_eq!(
+        micromark("5__6__78"),
+        "<p>5__6__78</p>",
+        "should not support strong intraword emphasis w/ `_` (2)"
+    );
+
+    assert_eq!(
+        micromark("пристаням__стремятся__"),
+        "<p>пристаням__стремятся__</p>",
+        "should not support strong intraword emphasis w/ `_` (3)"
+    );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("__foo, __bar__, baz__"),
+    //     "<p><strong>foo, <strong>bar</strong>, baz</strong></p>",
+    //     "should support nested strong emphasis"
+    // );
+
+    assert_eq!(
+        micromark("foo-__(bar)__"),
+        "<p>foo-<strong>(bar)</strong></p>",
+        "should support strong emphasis if the opening is both left and right flanking, if it’s preceded by punctuation"
+    );
+
+    // Rule 7.
+    assert_eq!(
+        micromark("**foo bar **"),
+        "<p>**foo bar **</p>",
+        "should not support strong emphasis w/ `*` if the closing is preceded by whitespace"
+    );
+
+    assert_eq!(
+        micromark("**(**foo)"),
+        "<p>**(**foo)</p>",
+        "should not support strong emphasis w/ `*` if the closing is preceded by punctuation and followed by something else"
+    );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("*(**foo**)*"),
+    //     "<p><em>(<strong>foo</strong>)</em></p>",
+    //     "should support strong emphasis in emphasis"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark(
+    //         "**Gomphocarpus (*Gomphocarpus physocarpus*, syn.\n*Asclepias physocarpa*)**"
+    //     ),
+    //     "<p><strong>Gomphocarpus (<em>Gomphocarpus physocarpus</em>, syn.\n<em>Asclepias physocarpa</em>)</strong></p>",
+    //     "should support emphasis in strong emphasis (1)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("**foo \"*bar*\" foo**"),
+    //     "<p><strong>foo &quot;<em>bar</em>&quot; foo</strong></p>",
+    //     "should support emphasis in strong emphasis (2)"
+    // );
+
+    assert_eq!(
+        micromark("**foo**bar"),
+        "<p><strong>foo</strong>bar</p>",
+        "should support strong intraword emphasis"
+    );
+
+    // Rule 8.
+    assert_eq!(
+        micromark("__foo bar __"),
+        "<p>__foo bar __</p>",
+        "should not support strong emphasis w/ `_` if the closing is preceded by whitespace"
+    );
+
+    assert_eq!(
+        micromark("__(__foo)"),
+        "<p>__(__foo)</p>",
+        "should not support strong emphasis w/ `_` if the closing is preceded by punctuation and followed by something else"
+    );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("_(__foo__)_"),
+    //     "<p><em>(<strong>foo</strong>)</em></p>",
+    //     "should support strong emphasis w/ `_` in emphasis"
+    // );
+
+    assert_eq!(
+        micromark("__foo__bar"),
+        "<p>__foo__bar</p>",
+        "should not support strong intraword emphasis w/ `_` (1)"
+    );
+
+    assert_eq!(
+        micromark("__пристаням__стремятся"),
+        "<p>__пристаням__стремятся</p>",
+        "should not support strong intraword emphasis w/ `_` (2)"
+    );
+
+    assert_eq!(
+        micromark("__foo__bar__baz__"),
+        "<p><strong>foo__bar__baz</strong></p>",
+        "should not support strong intraword emphasis w/ `_` (3)"
+    );
+
+    assert_eq!(
+        micromark("__(bar)__."),
+        "<p><strong>(bar)</strong>.</p>",
+        "should support strong emphasis if the opening is both left and right flanking, if it’s followed by punctuation"
+    );
+
+    // Rule 9.
+    assert_eq!(
+        micromark("*foo [bar](/url)*"),
+        "<p><em>foo <a href=\"/url\">bar</a></em></p>",
+        "should support content in emphasis"
+    );
+
+    assert_eq!(
+        micromark("*foo\nbar*"),
+        "<p><em>foo\nbar</em></p>",
+        "should support line endings in emphasis"
+    );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("_foo __bar__ baz_"),
+    //     "<p><em>foo <strong>bar</strong> baz</em></p>",
+    //     "should support nesting emphasis and strong (1)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("_foo _bar_ baz_"),
+    //     "<p><em>foo <em>bar</em> baz</em></p>",
+    //     "should support nesting emphasis and strong (2)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("__foo_ bar_"),
+    //     "<p><em><em>foo</em> bar</em></p>",
+    //     "should support nesting emphasis and strong (3)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("*foo *bar**"),
+    //     "<p><em>foo <em>bar</em></em></p>",
+    //     "should support nesting emphasis and strong (4)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("*foo **bar** baz*"),
+    //     "<p><em>foo <strong>bar</strong> baz</em></p>",
+    //     "should support nesting emphasis and strong (5)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("*foo**bar**baz*"),
+    //     "<p><em>foo<strong>bar</strong>baz</em></p>",
+    //     "should support nesting emphasis and strong (6)"
+    // );
+
+    assert_eq!(
+        micromark("*foo**bar*"),
+        "<p><em>foo**bar</em></p>",
+        "should not support adjacent emphasis in certain cases"
+    );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("***foo** bar*"),
+    //     "<p><em><strong>foo</strong> bar</em></p>",
+    //     "complex (1)"
+    // );
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("*foo **bar***"),
+    //     "<p><em>foo <strong>bar</strong></em></p>",
+    //     "complex (2)"
+    // );
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("*foo**bar***"),
+    //     "<p><em>foo<strong>bar</strong></em></p>",
+    //     "complex (3)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("foo***bar***baz"),
+    //     "<p>foo<em><strong>bar</strong></em>baz</p>",
+    //     "complex (a)"
+    // );
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("foo******bar*********baz"),
+    //     "<p>foo<strong><strong><strong>bar</strong></strong></strong>***baz</p>",
+    //     "complex (b)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("*foo **bar *baz* bim** bop*"),
+    //     "<p><em>foo <strong>bar <em>baz</em> bim</strong> bop</em></p>",
+    //     "should support indefinite nesting of emphasis (1)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("*foo [*bar*](/url)*"),
+    //     "<p><em>foo <a href=\"/url\"><em>bar</em></a></em></p>",
+    //     "should support indefinite nesting of emphasis (2)"
+    // );
+
+    assert_eq!(
+        micromark("** is not an empty emphasis"),
+        "<p>** is not an empty emphasis</p>",
+        "should not support empty emphasis"
+    );
+
+    assert_eq!(
+        micromark("**** is not an empty emphasis"),
+        "<p>**** is not an empty emphasis</p>",
+        "should not support empty strong emphasis"
+    );
+
+    // Rule 10.
+    assert_eq!(
+        micromark("**foo [bar](/url)**"),
+        "<p><strong>foo <a href=\"/url\">bar</a></strong></p>",
+        "should support content in strong emphasis"
+    );
+
+    assert_eq!(
+        micromark("**foo\nbar**"),
+        "<p><strong>foo\nbar</strong></p>",
+        "should support line endings in emphasis"
+    );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("__foo _bar_ baz__"),
+    //     "<p><strong>foo <em>bar</em> baz</strong></p>",
+    //     "should support nesting emphasis and strong (1)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("__foo __bar__ baz__"),
+    //     "<p><strong>foo <strong>bar</strong> baz</strong></p>",
+    //     "should support nesting emphasis and strong (2)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("____foo__ bar__"),
+    //     "<p><strong><strong>foo</strong> bar</strong></p>",
+    //     "should support nesting emphasis and strong (3)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("**foo **bar****"),
+    //     "<p><strong>foo <strong>bar</strong></strong></p>",
+    //     "should support nesting emphasis and strong (4)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("**foo *bar* baz**"),
+    //     "<p><strong>foo <em>bar</em> baz</strong></p>",
+    //     "should support nesting emphasis and strong (5)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("**foo*bar*baz**"),
+    //     "<p><strong>foo<em>bar</em>baz</strong></p>",
+    //     "should support nesting emphasis and strong (6)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("***foo* bar**"),
+    //     "<p><strong><em>foo</em> bar</strong></p>",
+    //     "should support nesting emphasis and strong (7)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("**foo *bar***"),
+    //     "<p><strong>foo <em>bar</em></strong></p>",
+    //     "should support nesting emphasis and strong (8)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("**foo *bar **baz**\nbim* bop**"),
+    //     "<p><strong>foo <em>bar <strong>baz</strong>\nbim</em> bop</strong></p>",
+    //     "should support indefinite nesting of emphasis (1)"
+    // );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("**foo [*bar*](/url)**"),
+    //     "<p><strong>foo <a href=\"/url\"><em>bar</em></a></strong></p>",
+    //     "should support indefinite nesting of emphasis (2)"
+    // );
+
+    assert_eq!(
+        micromark("__ is not an empty emphasis"),
+        "<p>__ is not an empty emphasis</p>",
+        "should not support empty emphasis"
+    );
+
+    assert_eq!(
+        micromark("____ is not an empty emphasis"),
+        "<p>____ is not an empty emphasis</p>",
+        "should not support empty strong emphasis"
+    );
+
+    // Rule 11.
+    assert_eq!(
+        micromark("foo ***"),
+        "<p>foo ***</p>",
+        "should not support emphasis around the same marker"
+    );
+
+    assert_eq!(
+        micromark("foo *\\**"),
+        "<p>foo <em>*</em></p>",
+        "should support emphasis around an escaped marker"
+    );
+
+    assert_eq!(
+        micromark("foo *_*"),
+        "<p>foo <em>_</em></p>",
+        "should support emphasis around the other marker"
+    );
+
+    assert_eq!(
+        micromark("foo *****"),
+        "<p>foo *****</p>",
+        "should not support strong emphasis around the same marker"
+    );
+
+    assert_eq!(
+        micromark("foo **\\***"),
+        "<p>foo <strong>*</strong></p>",
+        "should support strong emphasis around an escaped marker"
+    );
+
+    assert_eq!(
+        micromark("foo **_**"),
+        "<p>foo <strong>_</strong></p>",
+        "should support strong emphasis around the other marker"
+    );
+
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("**foo*"),
+    //     "<p>*<em>foo</em></p>",
+    //     "should support a superfluous marker at the start of emphasis"
+    // );
+
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("*foo**"),
+    //     "<p><em>foo</em>*</p>",
+    //     "should support a superfluous marker at the end of emphasis"
+    // );
+
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("***foo**"),
+    //     "<p>*<strong>foo</strong></p>",
+    //     "should support a superfluous marker at the start of strong"
+    // );
+
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("****foo*"),
+    //     "<p>***<em>foo</em></p>",
+    //     "should support multiple superfluous markers at the start of strong"
+    // );
+
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("**foo***"),
+    //     "<p><strong>foo</strong>*</p>",
+    //     "should support a superfluous marker at the end of strong"
+    // );
+
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("*foo****"),
+    //     "<p><em>foo</em>***</p>",
+    //     "should support multiple superfluous markers at the end of strong"
+    // );
+
+    // Rule 12.
+    assert_eq!(
+        micromark("foo ___"),
+        "<p>foo ___</p>",
+        "should not support emphasis around the same marker"
+    );
+
+    assert_eq!(
+        micromark("foo _\\__"),
+        "<p>foo <em>_</em></p>",
+        "should support emphasis around an escaped marker"
+    );
+
+    assert_eq!(
+        micromark("foo _X_"),
+        "<p>foo <em>X</em></p>",
+        "should support emphasis around the other marker"
+    );
+
+    assert_eq!(
+        micromark("foo _____"),
+        "<p>foo _____</p>",
+        "should not support strong emphasis around the same marker"
+    );
+
+    assert_eq!(
+        micromark("foo __\\___"),
+        "<p>foo <strong>_</strong></p>",
+        "should support strong emphasis around an escaped marker"
+    );
+
+    assert_eq!(
+        micromark("foo __X__"),
+        "<p>foo <strong>X</strong></p>",
+        "should support strong emphasis around the other marker"
+    );
+
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("__foo_"),
+    //     "<p>_<em>foo</em></p>",
+    //     "should support a superfluous marker at the start of emphasis"
+    // );
+
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("_foo__"),
+    //     "<p><em>foo</em>_</p>",
+    //     "should support a superfluous marker at the end of emphasis"
+    // );
+
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("___foo__"),
+    //     "<p>_<strong>foo</strong></p>",
+    //     "should support a superfluous marker at the start of strong"
+    // );
+
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("____foo_"),
+    //     "<p>___<em>foo</em></p>",
+    //     "should support multiple superfluous markers at the start of strong"
+    // );
+
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("__foo___"),
+    //     "<p><strong>foo</strong>_</p>",
+    //     "should support a superfluous marker at the end of strong"
+    // );
+
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("_foo____"),
+    //     "<p><em>foo</em>___</p>",
+    //     "should support multiple superfluous markers at the end of strong"
+    // );
+
+    // Rule 13.
+    assert_eq!(
+        micromark("**foo**"),
+        "<p><strong>foo</strong></p>",
+        "should support strong w/ `*`"
+    );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("*_foo_*"),
+    //     "<p><em><em>foo</em></em></p>",
+    //     "should support emphasis directly in emphasis w/ `_` in `*`"
+    // );
+
+    assert_eq!(
+        micromark("__foo__"),
+        "<p><strong>foo</strong></p>",
+        "should support strong w/ `_`"
+    );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("_*foo*_"),
+    //     "<p><em><em>foo</em></em></p>",
+    //     "should support emphasis directly in emphasis w/ `*` in `_`"
+    // );
+
+    // To do: nested emphasis.
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("****foo****"),
+    //     "<p><strong><strong>foo</strong></strong></p>",
+    //     "should support strong emphasis directly in strong emphasis w/ `*`"
+    // );
+
+    // To do: nested emphasis.
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("____foo____"),
+    //     "<p><strong><strong>foo</strong></strong></p>",
+    //     "should support strong emphasis directly in strong emphasis w/ `_`"
+    // );
+
+    // To do: nested emphasis.
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("******foo******"),
+    //     "<p><strong><strong><strong>foo</strong></strong></strong></p>",
+    //     "should support indefinite strong emphasis"
+    // );
+
+    // Rule 14.
+    // To do: nested emphasis.
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("***foo***"),
+    //     "<p><em><strong>foo</strong></em></p>",
+    //     "should support strong directly in emphasis w/ `*`"
+    // );
+
+    // To do: nested emphasis.
+    // To do: resizing remaining attention runs.
+    // assert_eq!(
+    //     micromark("___foo___"),
+    //     "<p><em><strong>foo</strong></em></p>",
+    //     "should support strong directly in emphasis w/ `_`"
+    // );
+
+    // Rule 15.
+    assert_eq!(
+        micromark("*foo _bar* baz_"),
+        "<p><em>foo _bar</em> baz_</p>",
+        "should not support mismatched emphasis"
+    );
+
+    // To do: nested emphasis.
+    // assert_eq!(
+    //     micromark("*foo __bar *baz bim__ bam*"),
+    //     "<p><em>foo <strong>bar *baz bim</strong> bam</em></p>",
+    //     "should not support mismatched strong emphasis"
+    // );
+
+    // Rule 16.
+    assert_eq!(
+        micromark("**foo **bar baz**"),
+        "<p>**foo <strong>bar baz</strong></p>",
+        "should not shortest strong possible"
+    );
+
+    assert_eq!(
+        micromark("*foo *bar baz*"),
+        "<p>*foo <em>bar baz</em></p>",
+        "should not shortest emphasis possible"
+    );
+
+    // Rule 17.
+    // To do: attention/link interplay.
+    // assert_eq!(
+    //     micromark("*[bar*](/url)"),
+    //     "<p>*<a href=\"/url\">bar*</a></p>",
+    //     "should not mismatch inside links (1)"
+    // );
+
+    // To do: attention/link interplay.
+    // assert_eq!(
+    //     micromark("_[bar_](/url)"),
+    //     "<p>_<a href=\"/url\">bar_</a></p>",
+    //     "should not mismatch inside links (1)"
+    // );
+
+    assert_eq!(
+        micromark_with_options("*<img src=\"foo\" title=\"*\"/>", DANGER),
+        "<p>*<img src=\"foo\" title=\"*\"/></p>",
+        "should not end inside HTML"
+    );
+
+    assert_eq!(
+        micromark_with_options("*<img src=\"foo\" title=\"*\"/>", DANGER),
+        "<p>*<img src=\"foo\" title=\"*\"/></p>",
+        "should not end emphasis inside HTML"
+    );
+
+    assert_eq!(
+        micromark_with_options("**<a href=\"**\">", DANGER),
+        "<p>**<a href=\"**\"></p>",
+        "should not end strong inside HTML (1)"
+    );
+
+    assert_eq!(
+        micromark_with_options("__<a href=\"__\">", DANGER),
+        "<p>__<a href=\"__\"></p>",
+        "should not end strong inside HTML (2)"
+    );
+
+    assert_eq!(
+        micromark("*a `*`*"),
+        "<p><em>a <code>*</code></em></p>",
+        "should not end emphasis inside code (1)"
+    );
+
+    assert_eq!(
+        micromark("_a `_`_"),
+        "<p><em>a <code>_</code></em></p>",
+        "should not end emphasis inside code (2)"
+    );
+
+    assert_eq!(
+        micromark("**a<http://foo.bar/?q=**>"),
+        "<p>**a<a href=\"http://foo.bar/?q=**\">http://foo.bar/?q=**</a></p>",
+        "should not end strong emphasis inside autolinks (1)"
+    );
+
+    assert_eq!(
+        micromark("__a<http://foo.bar/?q=__>"),
+        "<p>__a<a href=\"http://foo.bar/?q=__\">http://foo.bar/?q=__</a></p>",
+        "should not end strong emphasis inside autolinks (2)"
+    );
+
+    // To do: turning things off.
+    // assert_eq!(
+    //     micromark("*a*", {extensions: [{disable: {null: ["attention"]}}]}),
+    //     "<p>*a*</p>",
+    //     "should support turning off attention"
+    // );
+}