Move iterators into separate package

Also reduce API exposure and use standard library more - and fix bugs I
previously introduces in mongo.

graph/iterator/and_iterator_test.go

@@ -0,0 +1,149 @@
+// Copyright 2014 The Cayley Authors. All rights reserved.
+//
+// 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 iterator
+
+import (
+	"testing"
+
+	"github.com/google/cayley/graph"
+)
+
+// Make sure that tags work on the And.
+func TestTag(t *testing.T) {
+	fix1 := newFixed()
+	fix1.AddValue(234)
+	fix1.AddTag("foo")
+	and := NewAnd()
+	and.AddSubIterator(fix1)
+	and.AddTag("bar")
+	out := fix1.Tags()
+	if len(out) != 1 {
+		t.Errorf("Expected length 1, got %d", len(out))
+	}
+	if out[0] != "foo" {
+		t.Errorf("Cannot get tag back, got %s", out[0])
+	}
+
+	val, ok := and.Next()
+	if !ok {
+		t.Errorf("And did not next")
+	}
+	if val != 234 {
+		t.Errorf("Unexpected value")
+	}
+	tags := make(map[string]graph.TSVal)
+	and.TagResults(&tags)
+	if tags["bar"] != 234 {
+		t.Errorf("no bar tag")
+	}
+	if tags["foo"] != 234 {
+		t.Errorf("no foo tag")
+	}
+}
+
+// Do a simple itersection of fixed values.
+func TestAndAndFixedIterators(t *testing.T) {
+	fix1 := newFixed()
+	fix1.AddValue(1)
+	fix1.AddValue(2)
+	fix1.AddValue(3)
+	fix1.AddValue(4)
+	fix2 := newFixed()
+	fix2.AddValue(3)
+	fix2.AddValue(4)
+	fix2.AddValue(5)
+	and := NewAnd()
+	and.AddSubIterator(fix1)
+	and.AddSubIterator(fix2)
+	// Should be as big as smallest subiterator
+	size, accurate := and.Size()
+	if size != 3 {
+		t.Error("Incorrect size")
+	}
+	if !accurate {
+		t.Error("not accurate")
+	}
+
+	val, ok := and.Next()
+	if val != 3 || ok == false {
+		t.Error("Incorrect first value")
+	}
+
+	val, ok = and.Next()
+	if val != 4 || ok == false {
+		t.Error("Incorrect second value")
+	}
+
+	val, ok = and.Next()
+	if ok {
+		t.Error("Too many values")
+	}
+
+}
+
+// If there's no intersection, the size should still report the same,
+// but there should be nothing to Next()
+func TestNonOverlappingFixedIterators(t *testing.T) {
+	fix1 := newFixed()
+	fix1.AddValue(1)
+	fix1.AddValue(2)
+	fix1.AddValue(3)
+	fix1.AddValue(4)
+	fix2 := newFixed()
+	fix2.AddValue(5)
+	fix2.AddValue(6)
+	fix2.AddValue(7)
+	and := NewAnd()
+	and.AddSubIterator(fix1)
+	and.AddSubIterator(fix2)
+	// Should be as big as smallest subiterator
+	size, accurate := and.Size()
+	if size != 3 {
+		t.Error("Incorrect size")
+	}
+	if !accurate {
+		t.Error("not accurate")
+	}
+
+	_, ok := and.Next()
+	if ok {
+		t.Error("Too many values")
+	}
+
+}
+
+func TestAllIterators(t *testing.T) {
+	all1 := NewInt64(1, 5)
+	all2 := NewInt64(4, 10)
+	and := NewAnd()
+	and.AddSubIterator(all2)
+	and.AddSubIterator(all1)
+
+	val, ok := and.Next()
+	if val.(int64) != 4 || ok == false {
+		t.Error("Incorrect first value")
+	}
+
+	val, ok = and.Next()
+	if val.(int64) != 5 || ok == false {
+		t.Error("Incorrect second value")
+	}
+
+	val, ok = and.Next()
+	if ok {
+		t.Error("Too many values")
+	}
+
+}