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merge_iterator_test.go

merge_iterator_test.go - Overview​

This file contains tests for the MergeIterator implementation, ensuring it correctly merges multiple iterators, handles duplicates, and supports both forward and reverse iteration. It also includes a SimpleIterator to facilitate testing.

Detailed Documentation​

SimpleIterator​

type SimpleIterator struct {
	keys     [][]byte
	vals     [][]byte
	idx      int
	reversed bool
}

A simple iterator implementation for testing purposes.

  • keys: The keys to iterate over.
  • vals: The values corresponding to the keys.
  • idx: The current index.
  • reversed: Indicates whether the iterator is reversed.

closeCount​

var (
	closeCount int
)

A package-level variable to track the number of times the Close method is called on SimpleIterator instances.

(*SimpleIterator) Close() error​

func (s *SimpleIterator) Close() error

Increments closeCount and returns nil.

  • Returns: error - Always nil.

(*SimpleIterator) Next()​

func (s *SimpleIterator) Next()

Moves the iterator to the next position, either forward or backward depending on the reversed flag.

(*SimpleIterator) Rewind()​

func (s *SimpleIterator) Rewind()

Resets the iterator to the beginning (or end if reversed).

(*SimpleIterator) Seek(key []byte)​

func (s *SimpleIterator) Seek(key []byte)

Seeks to the given key.

  • Parameters:
    • key: The key to seek to.

(*SimpleIterator) Key() []byte​

func (s *SimpleIterator) Key() []byte

Returns the key at the current index.

  • Returns: []byte - The key at the current index.

(*SimpleIterator) Value() y.ValueStruct​

func (s *SimpleIterator) Value() y.ValueStruct

Returns the value at the current index.

  • Returns: y.ValueStruct - The value at the current index.

(*SimpleIterator) Valid() bool​

func (s *SimpleIterator) Valid() bool

Checks if the current index is valid.

  • Returns: bool - True if the current index is valid, false otherwise.

newSimpleIterator(keys []string, vals []string, reversed bool) *SimpleIterator​

func newSimpleIterator(keys []string, vals []string, reversed bool) *SimpleIterator

Creates a new SimpleIterator.

  • Parameters:
    • keys: The keys for the iterator.
    • vals: The values for the iterator.
    • reversed: Whether the iterator should be reversed.
  • Returns: *SimpleIterator - A pointer to the new SimpleIterator.

getAll(it y.Iterator) ([]string, []string)​

func getAll(it y.Iterator) ([]string, []string)

Collects all keys and values from an iterator into string slices.

  • Parameters:
    • it: The iterator to read from.
  • Returns: ([]string, []string) - A tuple of string slices containing the keys and values.

closeAndCheck(t *testing.T, it y.Iterator, expected int)​

func closeAndCheck(t *testing.T, it y.Iterator, expected int)

Closes the iterator and asserts that the closeCount matches the expected value.

  • Parameters:
    • t: The testing object.
    • it: The iterator to close.
    • expected: The expected value of closeCount.

TestSimpleIterator(t *testing.T)​

func TestSimpleIterator(t *testing.T)

Tests the basic functionality of the SimpleIterator.

reversed(a []string) []string​

func reversed(a []string) []string

Reverses a string slice.

  • Parameters:
    • a: The string slice to reverse.
  • Returns: []string - The reversed string slice.

TestMergeSingle(t *testing.T)​

func TestMergeSingle(t *testing.T)

Tests merging a single iterator using NewMergeIterator.

TestMergeSingleReversed(t *testing.T)​

func TestMergeSingleReversed(t *testing.T)

Tests merging a single reversed iterator.

TestMergeMore(t *testing.T)​

func TestMergeMore(t *testing.T)

Tests merging multiple iterators, including cases with and without duplicates, in both forward and reverse directions.

TestMergeIteratorNested(t *testing.T)​

func TestMergeIteratorNested(t *testing.T)

Tests nested MergeIterator to ensure the Iterator interface is satisfied.

TestMergeIteratorSeek(t *testing.T)​

func TestMergeIteratorSeek(t *testing.T)

Tests the Seek functionality of the MergeIterator.

TestMergeIteratorSeekReversed(t *testing.T)​

func TestMergeIteratorSeekReversed(t *testing.T)

Tests the Seek functionality of the MergeIterator in reversed order.

TestMergeIteratorSeekInvalid(t *testing.T)​

func TestMergeIteratorSeekInvalid(t *testing.T)

Tests Seek with an invalid key, ensuring the iterator becomes invalid.

TestMergeIteratorSeekInvalidReversed(t *testing.T)​

func TestMergeIteratorSeekInvalidReversed(t *testing.T)

Tests Seek with an invalid key in reversed order, ensuring the iterator becomes invalid.

TestMergeIteratorDuplicate(t *testing.T)​

func TestMergeIteratorDuplicate(t *testing.T)

Tests the MergeIterator with duplicate keys in the input iterators.

TestMergeDuplicates(t *testing.T)​

func TestMergeDuplicates(t *testing.T)

Tests merging iterators containing duplicate keys.