testcase "parse data from a file" {
  // We need to specify TestChecker here in order to use lib/testing.
  success TestChecker
}

unittest test {
  String raw <- FileTesting.forceReadFile($ExprLookup[MODULE_PATH]$ + "/test-data.txt")
  ErrorOr<TestData> actual <- TestDataParser.create() `ParseState:consumeAll` raw

  // Since TestData.create specifies labels, we _must_ use them here.
  TestData expected <- TestData.create(
      name:        "example data",
      description: "THIS_IS_A_TOKEN",
      boolean:     false)

  // Since TestData refines TestCompare<TestData>, we can use Matches:value.
  \ actual.tryValue() `Matches:value` expected

  // If we want to check the ErrorOr<TestData> itself, we need a
  // ValueMatcher<TestData> to pass to CheckErrorOr:value. We can do this with
  // CheckValue:using to create one from TestCompare<TestData>.
  \ actual `Matches:with` CheckErrorOr:value(CheckValue:using(expected))

  // Matches:with uses more general matchers such as CheckValue:equals. &. below
  // will call the function iff the value isn't empty. This is needed in order
  // to call functions on optional values.
  \ actual.tryValue()&.name()        `Matches:with` CheckValue:equals("example data")
  \ actual.tryValue()&.description() `Matches:with` CheckValue:equals("THIS_IS_A_TOKEN")
  \ actual.tryValue()&.boolean()     `Matches:with` CheckValue:equals(false)
}