Add missing tests for attributesMap (open-telemetry#1337)

* Rename sdk/trace/attributesMap.go -> sdk/trace/attributesmap.go

Signed-off-by: Daniil Rutskiy <dstdfx@gmail.com>

* Add missing tests for attributesMap

Signed-off-by: Daniil Rutskiy <dstdfx@gmail.com>

* Update CHANGELOG.md

Signed-off-by: Daniil Rutskiy <dstdfx@gmail.com>

* Add missing license header

Signed-off-by: Daniil Rutskiy <dstdfx@gmail.com>

* Delete underscores in test names

Signed-off-by: Daniil Rutskiy <dstdfx@gmail.com>

* Tests clean up

Signed-off-by: Daniil Rutskiy <dstdfx@gmail.com>

CHANGELOG.md

@@ -17,6 +17,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Add an opencensus to opentelemetry tracing bridge. (#1305)
 - Add a parent context argument to `SpanProcessor.OnStart` to follow the specification. (#1333)
 - Add an opencensus binary propagation implementation. (#1334)
+- Add missing tests for `sdk/trace/attributes_map.go`. (#1337)
 
 ### Changed
 

sdk/trace/attributesmap_test.go

@@ -0,0 +1,98 @@
+// Copyright The OpenTelemetry Authors
+//
+// 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 trace
+
+import (
+	"fmt"
+	"testing"
+
+	"go.opentelemetry.io/otel/label"
+	export "go.opentelemetry.io/otel/sdk/export/trace"
+)
+
+const testKeyFmt = "test-key-%d"
+
+func TestAttributesMap(t *testing.T) {
+	wantCapacity := 128
+	attrMap := newAttributesMap(wantCapacity)
+
+	for i := 0; i < 256; i++ {
+		attrMap.add(label.Int(fmt.Sprintf(testKeyFmt, i), i))
+	}
+	if attrMap.capacity != wantCapacity {
+		t.Errorf("attrMap.capacity: got '%d'; want '%d'", attrMap.capacity, wantCapacity)
+	}
+
+	if attrMap.droppedCount != wantCapacity {
+		t.Errorf("attrMap.droppedCount: got '%d'; want '%d'", attrMap.droppedCount, wantCapacity)
+	}
+
+	for i := 0; i < wantCapacity; i++ {
+		key := label.Key(fmt.Sprintf(testKeyFmt, i))
+		_, ok := attrMap.attributes[key]
+		if ok {
+			t.Errorf("key %q should be dropped", testKeyFmt)
+		}
+	}
+	for i := wantCapacity; i < 256; i++ {
+		key := label.Key(fmt.Sprintf(testKeyFmt, i))
+		_, ok := attrMap.attributes[key]
+		if !ok {
+			t.Errorf("key %q should not be dropped", key)
+		}
+	}
+}
+
+func TestAttributesMapGetOldestRemoveOldest(t *testing.T) {
+	attrMap := newAttributesMap(128)
+
+	for i := 0; i < 128; i++ {
+		attrMap.add(label.Int(fmt.Sprintf(testKeyFmt, i), i))
+	}
+
+	attrMap.removeOldest()
+	attrMap.removeOldest()
+	attrMap.removeOldest()
+
+	for i := 0; i < 3; i++ {
+		key := label.Key(fmt.Sprintf(testKeyFmt, i))
+		_, ok := attrMap.attributes[key]
+		if ok {
+			t.Errorf("key %q should be removed", key)
+		}
+	}
+}
+
+func TestAttributesMapToSpanData(t *testing.T) {
+	attrMap := newAttributesMap(128)
+
+	for i := 0; i < 128; i++ {
+		attrMap.add(label.Int(fmt.Sprintf(testKeyFmt, i), i))
+	}
+
+	sd := &export.SpanData{}
+
+	attrMap.toSpanData(sd)
+
+	if attrMap.droppedCount != sd.DroppedAttributeCount {
+		t.Errorf("attrMap.droppedCount: got '%d'; want '%d'", attrMap.droppedCount, sd.DroppedAttributeCount)
+	}
+
+	gotAttrLen := len(attrMap.attributes)
+	wantAttrLen := len(sd.Attributes)
+	if gotAttrLen != wantAttrLen {
+		t.Errorf("len(attrMap.attributes): got '%d'; want '%d'", gotAttrLen, wantAttrLen)
+	}
+}