如何在Java中编写测试保障Markdown转HTML功能正常？

Hey there! I see you've spent days working on your markdownToHtml method in TextUtils.java—let's put together some solid tests to make sure it works as expected. First, let's recap your current code snippet for context:

protected static String markdownToHtml(String text) { 
    text = text.replaceAll("<([^a-zA-Z/])", "<$1"); 
    // https://github.com/enketo/enketo-transformer/blob/master/src/markdown.js 
    // span - replaced < and > with <> 
    text = ReplaceCallback.replace("(?s)<\\s?span([^\\/\n]*)>((?:(?!<\\/).)+)<\\/\\s?span\\s?>", text, createSpan); 
    // strong 
    text = text.replaceAll("/__....

Now, let's break down how to test this effectively.

1. Choose Your Testing Tools #

For Java, the standard setup is:

• JUnit 5: The de facto framework for unit testing.
• AssertJ: Makes assertions more readable and flexible (e.g., assertThat(actual).isEqualTo(expected)).
• (Optional) Mockito: Only needed if ReplaceCallback or createSpan have external dependencies; static utility methods won't require this.

2. Core Test Scenarios to Cover #

You'll want to test every part of your implementation, plus edge cases. Here are the key scenarios:

a. Special Character Escaping #

Verify your first regex handles escaped < characters correctly when they aren't part of a tag:

@Test
void testSpecialCharacterEscaping() {
    String input = "<5 is less than <span>10</span>";
    String expected = "&amp;lt;5 is less than <span>10</span>";
    String actual = TextUtils.markdownToHtml(input);
    assertThat(actual).isEqualTo(expected);
}

b. Span Tag Conversion #

Test various span cases to ensure your regex handles spacing, attributes, and multi-line content:

@Test
void testSpanTagConversion() {
    // Basic span with no attributes
    String input1 = "<span>Highlighted text</span>";
    String expected1 = "<span>Highlighted text</span>";
    assertThat(TextUtils.markdownToHtml(input1)).isEqualTo(expected1);

    // Span with attributes and extra spaces
    String input2 = "&lt; span class=\"warning\" id=\"alert\" &gt;Warning message&lt;/ span &gt;";
    String expected2 = "<span class=\"warning\" id=\"alert\">Warning message</span>";
    assertThat(TextUtils.markdownToHtml(input2)).isEqualTo(expected2);

    // Multi-line span content
    String input3 = "&lt;span&gt;Line 1\nLine 2\nLine 3&lt;/span&gt;";
    String expected3 = "<span>Line 1\nLine 2\nLine 3</span>";
    assertThat(TextUtils.markdownToHtml(input3)).isEqualTo(expected3);
}

c. Strong (Bold) Text Conversion #

Since you started implementing bold text with __, test basic and edge cases for this feature:

@Test
void testStrongTextConversion() {
    // Basic bold text
    String input1 = "__This is bold__";
    String expected1 = "<strong>This is bold</strong>";
    assertThat(TextUtils.markdownToHtml(input1)).isEqualTo(expected1);

    // Bold text within other content
    String input2 = "Normal text __bold part__ more normal text";
    String expected2 = "Normal text <strong>bold part</strong> more normal text";
    assertThat(TextUtils.markdownToHtml(input2)).isEqualTo(expected2);

    // Incomplete bold syntax (should remain unchanged)
    String input3 = "__Unclosed bold";
    String expected3 = "__Unclosed bold";
    assertThat(TextUtils.markdownToHtml(input3)).isEqualTo(expected3);
}

d. Mixed Scenarios #

Test combinations of spans, bold text, and special characters to ensure they work together seamlessly:

@Test
void testMixedMarkdownElements() {
    String input = "<span class=\"note\">Remember: __Always test your code__ < 100%</span>";
    String expected = "<span class=\"note\">Remember: <strong>Always test your code</strong> &amp;lt; 100%</span>";
    assertThat(TextUtils.markdownToHtml(input)).isEqualTo(expected);
}

e. Edge Cases #

Don't forget these tricky scenarios that often break converters:

@Test
void testEdgeCases() {
    // Empty string
    assertThat(TextUtils.markdownToHtml("")).isEqualTo("");

    // Pure whitespace
    assertThat(TextUtils.markdownToHtml("   \n   ")).isEqualTo("   \n   ");

    // No markdown syntax at all
    assertThat(TextUtils.markdownToHtml("Just plain old text")).isEqualTo("Just plain old text");
}

3. Optimize with Parameterized Tests #

Instead of writing separate methods for similar cases, use parameterized tests to run multiple input-output pairs in one method. This keeps your test code clean and scalable:

@ParameterizedTest
@CsvSource({
    "&lt;span&gt;Test&lt;/span&gt;, <span>Test</span>",
    "&lt; span id=\"test\" &gt;Hi&lt;/ span &gt;, <span id=\"test\">Hi</span>",
    "__Bold__, <strong>Bold</strong>",
    "Text __with bold__ and &lt;span&gt;span&lt;/span&gt;, Text <strong>with bold</strong> and <span>span</span>"
})
void testMarkdownConversion(String input, String expected) {
    assertThat(TextUtils.markdownToHtml(input)).isEqualTo(expected);
}

4. Extra Tips #

• Debug Failed Tests: If a test fails, print the input, actual output, and expected output to spot subtle differences easily.
• Keep Tests Focused: Each test should verify one specific behavior—avoid overloading a single test with multiple unrelated checks.
• Update Tests As You Extend: Every time you add a new Markdown feature (like italics or links), add corresponding test cases immediately.

内容的提问来源于stack exchange，提问作者didicodes