refactor(ffi/iterator): move tests into a separate file (#1543)

## Why this should be merged
As discussed with @alarso16 before, this moves the iterator-related
tests into a separate file to keep things organized.

## How this works
Moves iterator-related tests out of `firewood_test.go` into their own
file.

## How this was tested
Existing go tests.

## Need to be documented in RELEASES.md?
N/A

Author: AminR443

ffi/firewood_test.go

@@ -1296,321 +1296,6 @@ func TestFjallStore(t *testing.T) {
 	}
 }
 
-type kvIter interface {
-	SetBatchSize(int)
-	Next() bool
-	Key() []byte
-	Value() []byte
-	Err() error
-	Drop() error
-}
-type borrowIter struct{ it *Iterator }
-
-func (b *borrowIter) SetBatchSize(batchSize int) { b.it.SetBatchSize(batchSize) }
-func (b *borrowIter) Next() bool                 { return b.it.NextBorrowed() }
-func (b *borrowIter) Key() []byte                { return b.it.Key() }
-func (b *borrowIter) Value() []byte              { return b.it.Value() }
-func (b *borrowIter) Err() error                 { return b.it.Err() }
-func (b *borrowIter) Drop() error                { return b.it.Drop() }
-
-func assertIteratorYields(r *require.Assertions, it kvIter, keys [][]byte, vals [][]byte) {
-	i := 0
-	for ; it.Next(); i += 1 {
-		r.Equal(keys[i], it.Key())
-		r.Equal(vals[i], it.Value())
-	}
-	r.NoError(it.Err())
-	r.Equal(len(keys), i)
-}
-
-type iteratorConfigFn = func(it kvIter) kvIter
-
-var iterConfigs = map[string]iteratorConfigFn{
-	"Owned":    func(it kvIter) kvIter { return it },
-	"Borrowed": func(it kvIter) kvIter { return &borrowIter{it: it.(*Iterator)} },
-	"Single": func(it kvIter) kvIter {
-		it.SetBatchSize(1)
-		return it
-	},
-	"Batched": func(it kvIter) kvIter {
-		it.SetBatchSize(100)
-		return it
-	},
-}
-
-func runIteratorTestForModes(t *testing.T, fn func(*testing.T, iteratorConfigFn), modes ...string) {
-	testName := strings.Join(modes, "/")
-	t.Run(testName, func(t *testing.T) {
-		r := require.New(t)
-		fn(t, func(it kvIter) kvIter {
-			for _, m := range modes {
-				config, ok := iterConfigs[m]
-				r.Truef(ok, "specified config mode %s does not exist", m)
-				it = config(it)
-			}
-			return it
-		})
-	})
-}
-
-func runIteratorTestForAllModes(parentT *testing.T, fn func(*testing.T, iteratorConfigFn)) {
-	for _, dataMode := range []string{"Owned", "Borrowed"} {
-		for _, batchMode := range []string{"Single", "Batched"} {
-			runIteratorTestForModes(parentT, fn, batchMode, dataMode)
-		}
-	}
-}
-
-// Tests that basic iterator functionality works
-func TestIter(t *testing.T) {
-	r := require.New(t)
-	db := newTestDatabase(t)
-	keys, vals := kvForTest(100)
-	_, err := db.Update(keys, vals)
-	r.NoError(err)
-
-	runIteratorTestForAllModes(t, func(t *testing.T, cfn iteratorConfigFn) {
-		r := require.New(t)
-		rev, err := db.LatestRevision()
-		r.NoError(err)
-		it, err := rev.Iter(nil)
-		r.NoError(err)
-		t.Cleanup(func() {
-			r.NoError(it.Drop())
-			r.NoError(rev.Drop())
-		})
-
-		assertIteratorYields(r, cfn(it), keys, vals)
-	})
-}
-
-func TestIterOnRoot(t *testing.T) {
-	r := require.New(t)
-	db := newTestDatabase(t)
-	keys, vals := kvForTest(240)
-	firstRoot, err := db.Update(keys[:80], vals[:80])
-	r.NoError(err)
-	secondRoot, err := db.Update(keys[80:160], vals[80:160])
-	r.NoError(err)
-	thirdRoot, err := db.Update(keys[160:], vals[160:])
-	r.NoError(err)
-
-	runIteratorTestForAllModes(t, func(t *testing.T, cfn iteratorConfigFn) {
-		r := require.New(t)
-		r1, err := db.Revision(firstRoot)
-		r.NoError(err)
-		h1, err := r1.Iter(nil)
-		r.NoError(err)
-		t.Cleanup(func() {
-			r.NoError(h1.Drop())
-			r.NoError(r1.Drop())
-		})
-
-		r2, err := db.Revision(secondRoot)
-		r.NoError(err)
-		h2, err := r2.Iter(nil)
-		r.NoError(err)
-		t.Cleanup(func() {
-			r.NoError(h2.Drop())
-			r.NoError(r2.Drop())
-		})
-
-		r3, err := db.Revision(thirdRoot)
-		r.NoError(err)
-		h3, err := r3.Iter(nil)
-		r.NoError(err)
-		t.Cleanup(func() {
-			r.NoError(h3.Drop())
-			r.NoError(r3.Drop())
-		})
-
-		assertIteratorYields(r, cfn(h1), keys[:80], vals[:80])
-		assertIteratorYields(r, cfn(h2), keys[:160], vals[:160])
-		assertIteratorYields(r, cfn(h3), keys, vals)
-	})
-}
-
-func TestIterOnProposal(t *testing.T) {
-	r := require.New(t)
-	db := newTestDatabase(t)
-	keys, vals := kvForTest(240)
-	_, err := db.Update(keys, vals)
-	r.NoError(err)
-
-	runIteratorTestForAllModes(t, func(t *testing.T, cfn iteratorConfigFn) {
-		r := require.New(t)
-		updatedValues := make([][]byte, len(vals))
-		copy(updatedValues, vals)
-
-		changedKeys := make([][]byte, 0)
-		changedVals := make([][]byte, 0)
-		for i := 0; i < len(vals); i += 4 {
-			changedKeys = append(changedKeys, keys[i])
-			newVal := []byte{byte(i)}
-			changedVals = append(changedVals, newVal)
-			updatedValues[i] = newVal
-		}
-		p, err := db.Propose(changedKeys, changedVals)
-		r.NoError(err)
-		it, err := p.Iter(nil)
-		r.NoError(err)
-		t.Cleanup(func() {
-			r.NoError(it.Drop())
-		})
-
-		assertIteratorYields(r, cfn(it), keys, updatedValues)
-	})
-}
-
-// Tests that the iterator still works after proposal is committed
-func TestIterAfterProposalCommit(t *testing.T) {
-	r := require.New(t)
-	db := newTestDatabase(t)
-
-	keys, vals := kvForTest(10)
-	p, err := db.Propose(keys, vals)
-	r.NoError(err)
-
-	it, err := p.Iter(nil)
-	r.NoError(err)
-	t.Cleanup(func() {
-		r.NoError(it.Drop())
-	})
-
-	err = p.Commit()
-	r.NoError(err)
-
-	// iterate after commit
-	// because iterator hangs on the nodestore reference of proposal
-	// the nodestore won't be dropped until we drop the iterator
-	assertIteratorYields(r, it, keys, vals)
-}
-
-// Tests that the iterator on latest revision works properly after a proposal commit
-func TestIterUpdate(t *testing.T) {
-	r := require.New(t)
-	db := newTestDatabase(t)
-
-	keys, vals := kvForTest(10)
-	_, err := db.Update(keys, vals)
-	r.NoError(err)
-
-	// get an iterator on latest revision
-	rev, err := db.LatestRevision()
-	r.NoError(err)
-	it, err := rev.Iter(nil)
-	r.NoError(err)
-	t.Cleanup(func() {
-		r.NoError(it.Drop())
-		r.NoError(rev.Drop())
-	})
-
-	// update the database
-	keys2, vals2 := kvForTest(10)
-	_, err = db.Update(keys2, vals2)
-	r.NoError(err)
-
-	// iterate after commit
-	// because iterator is fixed on the revision hash, it should return the initial values
-	assertIteratorYields(r, it, keys, vals)
-}
-
-// Tests the iterator's behavior after exhaustion, should safely return empty item/batch, indicating done
-func TestIterDone(t *testing.T) {
-	r := require.New(t)
-	db := newTestDatabase(t)
-
-	keys, vals := kvForTest(18)
-	_, err := db.Update(keys, vals)
-	r.NoError(err)
-
-	// get an iterator on latest revision
-	rev, err := db.LatestRevision()
-	r.NoError(err)
-	it, err := rev.Iter(nil)
-	r.NoError(err)
-	t.Cleanup(func() {
-		r.NoError(it.Drop())
-		r.NoError(rev.Drop())
-	})
-	// consume the iterator
-	assertIteratorYields(r, it, keys, vals)
-	// calling next again should be safe and return false
-	r.False(it.Next())
-	r.NoError(it.Err())
-
-	// get a new iterator
-	it2, err := rev.Iter(nil)
-	r.NoError(err)
-	// set batch size to 5
-	it2.SetBatchSize(5)
-	// consume the iterator
-	assertIteratorYields(r, it2, keys, vals)
-	// calling next again should be safe and return false
-	r.False(it.Next())
-	r.NoError(it.Err())
-}
-
-// Tests the iterator's behavior after revision is dropped, should safely
-// outlive the revision as it owns a reference to the revision in Rust.
-func TestIterOutlivesRevision(t *testing.T) {
-	r := require.New(t)
-	db := newTestDatabase(t, func(config *config) {
-		config.revisions = 2
-	})
-
-	keys, vals := kvForTest(30)
-	_, err := db.Update(keys[:10], vals[:10])
-	r.NoErrorf(err, "%T.Update(...)", db)
-	rev, err := db.LatestRevision()
-	r.NoErrorf(err, "%T.LatestRevision()", db)
-	it, err := rev.Iter(nil)
-	r.NoErrorf(err, "%T.Iter()", rev)
-	t.Cleanup(func() {
-		r.NoErrorf(it.Drop(), "%T.Drop()", it)
-	})
-
-	// Drop the revision right away to ensure reaping
-	r.NoErrorf(rev.Drop(), "%T.Drop()", rev)
-
-	// Commit two more times to force reaping of the first revision
-	_, err = db.Update(keys[10:20], vals[10:20])
-	r.NoErrorf(err, "%T.Update(...)", db)
-	_, err = db.Update(keys[20:], vals[20:])
-	r.NoErrorf(err, "%T.Update(...)", db)
-
-	// iterate after reaping
-	assertIteratorYields(r, it, keys[:10], vals[:10])
-}
-
-// Tests the iterator's behavior after proposal is dropped, should safely
-// outlive the proposal as it owns a reference to the view in Rust.
-func TestIterOutlivesProposal(t *testing.T) {
-	r := require.New(t)
-	db := newTestDatabase(t)
-
-	keys, vals := kvForTest(4)
-	p, err := db.Propose(keys[:2], vals[:2])
-	r.NoErrorf(err, "%T.Propose(...)", db)
-
-	it, err := p.Iter(nil)
-	r.NoErrorf(err, "%T.Iter()", p)
-	t.Cleanup(func() {
-		r.NoErrorf(it.Drop(), "%T.Drop()", it)
-	})
-	r.NoErrorf(p.Drop(), "%T.Drop()", p)
-
-	// This is necessary because the dropped proposal is referenced in
-	// the revision manager and cleanup only runs when commit is called.
-	// So here we create a new proposal with different keys, and commit
-	// to trigger cleanup of the dropped proposal.
-	p2, err := db.Propose(keys[2:], vals[2:])
-	r.NoErrorf(err, "%T.Propose(...)", db)
-	r.NoErrorf(p2.Commit(), "%T.Commit(...)", db)
-
-	assertIteratorYields(r, it, keys[:2], vals[:2])
-}
-
 // TestNilVsEmptyValue tests that nil values cause delete operations while
 // empty []byte{} values result in inserts with empty values.
 func TestNilVsEmptyValue(t *testing.T) {