Add a converter that finds gist URLs and converts these to gist short…

…codes for Hugo

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src/wp2hugo/internal/hugogenerator/hugo_generator_test.go

@@ -31,3 +31,16 @@ func TestFootnote(t *testing.T) {
 	const expectedMarkdown = "Some text[^1] with a footnote\n\n[^1]: Here we are: the footnote."
 	assert.True(t, strings.Contains(hugoPage.Markdown(), expectedMarkdown))
 }
+
+func TestMarkdownExtractorWithLink1(t *testing.T) {
+	const sampleHTMLInput = `<p><a href="https://gist.github.com/lawrencegripper/8e701b0d201e65af0f8bc9b8b0b14207">Gist Link</a></p>`
+	const expectedMarkdownOutput = `{{< gist lawrencegripper 8e701b0d201e65af0f8bc9b8b0b14207 >}}`
+
+	url1, err := url.Parse("https://example.com")
+	assert.Nil(t, err)
+	page, err := NewPage(nil, *url1, "author", "Title", nil, false, nil, nil, nil, sampleHTMLInput, nil, nil)
+	assert.Nil(t, err)
+	md, err := page.getMarkdown(nil, sampleHTMLInput, nil)
+	assert.Nil(t, err)
+	assert.Equal(t, expectedMarkdownOutput, *md)
+}