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Testing Emacs Fundamental Mode Modeline Processing in GitHub Linguist

This test file validates the fundamental Emacs modeline parsing functionality in the GitHub Linguist repository. It specifically tests how the system handles files with Emacs modelines that specify fundamental mode, ensuring proper language detection and syntax highlighting behavior.

Test Coverage Overview

The test coverage focuses on the specific handling of Emacs fundamental mode modeline declarations. It verifies that files marked with ‘// -*- fundamental -*-‘ are properly identified and processed without syntax highlighting.

Tests modeline parsing accuracy
Validates fundamental mode recognition
Verifies syntax highlighting suppression
Ensures correct language classification

Implementation Analysis

The testing approach uses a minimalist C-like code structure to demonstrate the fundamental mode behavior. The implementation specifically checks that the modeline directive overrides the default language detection that would normally apply to .c files.

Modeline directive placement testing
Language detection override verification
Syntax highlighting behavior validation

Technical Details

Test file extension: .c
Modeline format: // -*- fundamental -*-
Expected behavior: No syntax highlighting
Test environment: GitHub Linguist test suite

Best Practices Demonstrated

The test exemplifies best practices in modeline testing by using a clear, minimal test case that explicitly demonstrates the intended behavior. It follows the principle of isolation by testing a single specific feature – the fundamental mode modeline processing.

Clear test case isolation
Explicit expected behavior
Minimal reproduction case
Focused feature testing

github-linguist/linguist

test/fixtures/Data/Modelines/fundamentalEmacs.c

            
// -*- fundamental -*-

int main(int argc, char * argc[])
{
  this should not be syntax highlighted, even though it looks like c.
}