cursor seek wrongly seq'd to uninitialized return val, not arg

also added initial cursor test case
fixes #5

cursor.go

@@ -54,7 +54,7 @@ func newCursor(reader *reader) *Cursor {
 // Seek moves the cursor to the specified key
 func (c *Cursor) Seek(seek []byte) (key []byte, value []byte) {
 	for i, cursor := range c.mutationsCursors {
-		c.key[i], c.val[i] = cursor.Seek(key)
+		c.key[i], c.val[i] = cursor.Seek(seek)
 	}
 	c.updateCurr()
 	for c.checkCurrDeleted() {

cursor_merge.go

@@ -55,10 +55,10 @@ func newMergeCursor(reader *reader) *mergeCursor {
 
 func (c *mergeCursor) Seek(seek []byte) (key []byte, value []byte, deleted bool) {
 	for i, cursor := range c.mutationsCursors {
-		c.key[i], c.val[i] = cursor.Seek(key)
+		c.key[i], c.val[i] = cursor.Seek(seek)
 	}
 	for i, cursor := range c.deletionsCursors {
-		c.dkey[i], _ = cursor.Seek(key)
+		c.dkey[i], _ = cursor.Seek(seek)
 	}
 	c.updateCurr()
 	if c.currIsDel {

cursor_test.go

@@ -0,0 +1,71 @@
+//  Copyright (c) 2016 Couchbase, Inc.
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the
+//  License. You may obtain a copy of the License at
+//    http://www.apache.org/licenses/LICENSE-2.0
+//  Unless required by applicable law or agreed to in writing,
+//  software distributed under the License is distributed on an "AS
+//  IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+//  express or implied. See the License for the specific language
+//  governing permissions and limitations under the License.
+
+package cellar
+
+import (
+	"os"
+	"testing"
+)
+
+func TestCellarCursorSimple(t *testing.T) {
+	defer os.RemoveAll("test")
+
+	c, err := Open("test", testOptionsNoAutoMerge)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+
+	// let's write some data
+	err = c.Update(func(tx *Tx) error {
+		putKvPairs(tx, 0, 100)
+		return nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// lets try a cursor
+	err = c.View(func(tx *Tx) error {
+		c := tx.Cursor()
+
+		k, _ := c.Next()
+		if k != nil {
+			t.Errorf("next on cursor before positioning expects nil, got key %s", string(k))
+		}
+
+		// seek to beginning
+		k, _ = c.Seek([]byte(""))
+		if string(k) != "k0000000000000000" {
+			t.Errorf("expected to see key 'k0000000000000000' got %s", string(k))
+		}
+
+		// seek further ahead
+		k, _ = c.Seek([]byte("k0000000000000004"))
+		if string(k) != "k0000000000000004" {
+			t.Errorf("expected to see key 'k0000000000000004' got %s", string(k))
+		}
+
+		// next after seq
+		k, _ = c.Next()
+		if string(k) != "k0000000000000005" {
+			t.Errorf("expected to see key 'k0000000000000005' got %s", string(k))
+		}
+
+		return nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+}