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Header Extensions

server_testing provides utilities for working with HTTP headers in tests through the HttpHeaderExtension.

Converting Headers to Map​

The toMap() extension method converts HttpHeaders to a Map for easier manipulation:

test('header manipulation', () {
  final response = await client.get('/api');
  
  // Get headers as map
  final headerMap = response.headers.toMap();
  
  // Access header values
  final contentType = headerMap['content-type'];
  final authorization = headerMap['authorization'];
  
  // Headers are preserved as lists
  expect(headerMap['accept'], isList);
});

Working with Header Maps​

Use the header map for testing and manipulation:

test('verify headers', () async {
  final response = await client.get('/api');
  final headers = response.headers.toMap();
  
  // Check header existence
  expect(headers.containsKey('content-type'), isTrue);
  
  // Check header values
  expect(
    headers['content-type']?[0],
    equals('application/json')
  );
  
  // Check multiple values
  expect(
    headers['accept']?.length,
    greaterThan(1)
  );
});