intellij-sdk-code-samples/tutorials/writing_tests_for_plugins/parsing_test.md

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2. Parsing Test

The first test checks if the Simple Language parser, implemented in the Lexer and Parser Definition section of the Custom Language Support Tutorial, works as expected.

2.1. Update Grammar and Regenerate the Parser

Before creating the parsing test, ensure the parser definition (Simple.bnf) includes the lines shown below. These additional lines facilitate testing incorrect keys.

If the lines below are not present in Simple.bnf, replace the existing property definition with the lines below. Don't forget to regenerate the parser after updating the file! Right-click on the Simple.bnf file and select Generate Parser Code.

property ::= (KEY? SEPARATOR VALUE?) | KEY {
  pin=3
  recoverWhile="recover_property"
  mixin="org.intellij.sdk.language.psi.impl.SimpleNamedElementImpl"
  implements="org.intellij.sdk.language.psi.SimpleNamedElement"
  methods=[getKey getValue getName setName getNameIdentifier getPresentation]
}
private recover_property ::= !(KEY|SEPARATOR|COMMENT)

2.2. Define Input Test Data

Create the ParsingTestData.simple properties file in the testData folder. Note the last few lines define a purposely incorrect key.

{% include /code_samples/simple_language_plugin/src/test/testData/ParsingTestData.simple %}

2.3. Copy the Expected PSI Tree

The easiest way to get the expected PSI structure for any file is to use the PSI Viewer. Run the project and use Tools | View PSI Structure.

Use the Copy PSI button to copy the expected PSI structure to the clipboard.

2.3. Define the Output Reference Test Data

Create a file ParsingTestData.txt with the copied PSI tree.

{% include /code_samples/simple_language_plugin/src/test/testData/ParsingTestData.txt %}

2.4. Define a Parsing Test

Subclass ParsingTestCase to create SimpleParsingTest:

{% include /code_samples/simple_language_plugin/src/test/java/org/intellij/sdk/language/SimpleParsingTest.java %}

2.5. Run the Test

Run the test by:

• Opening the Gradle Tool Window.
• Drill down to the simple_language_plugin. You may need to reimport it as a Gradle project.
• Drill down under simple_language_plugin to the test task under verification.
• Run the test task.