Add unit tests to attribute filters (#226) (open-telemetry#1204)

Add missing unit tests to the currently implemented attribute filters (`stringAttributeFilter` and `numericAttributeFilter`)

**Link to tracking Issue:** 
This can be considered part of #226

processor/samplingprocessor/tailsamplingprocessor/sampling/numeric_tag_filter_test.go

@@ -0,0 +1,96 @@
+// 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 sampling
+
+import (
+	"math"
+	"testing"
+
+	tracepb "github.com/census-instrumentation/opencensus-proto/gen-go/trace/v1"
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+	"go.uber.org/zap"
+
+	"go.opentelemetry.io/collector/consumer/consumerdata"
+)
+
+func TestNumericTagFilter(t *testing.T) {
+
+	filter := NewNumericAttributeFilter(zap.NewNop(), "example", math.MinInt32, math.MaxInt32)
+
+	cases := []struct {
+		Desc     string
+		Trace    *TraceData
+		Decision Decision
+	}{
+		{
+			Desc:     "nonmatching span attribute",
+			Trace:    newTraceIntAttrs("non_matching", math.MinInt32),
+			Decision: NotSampled,
+		},
+		{
+			Desc:     "span attribute with lower limit",
+			Trace:    newTraceIntAttrs("example", math.MinInt32),
+			Decision: Sampled,
+		},
+		{
+			Desc:     "span attribute with upper limit",
+			Trace:    newTraceIntAttrs("example", math.MaxInt32),
+			Decision: Sampled,
+		},
+		{
+			Desc:     "span attribute below min limit",
+			Trace:    newTraceIntAttrs("example", math.MinInt32-1),
+			Decision: NotSampled,
+		},
+		{
+			Desc:     "span attribute above max limit",
+			Trace:    newTraceIntAttrs("example", math.MaxInt32+1),
+			Decision: NotSampled,
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.Desc, func(t *testing.T) {
+			u, _ := uuid.NewRandom()
+			decision, err := filter.Evaluate(u[:], c.Trace)
+			assert.NoError(t, err)
+			assert.Equal(t, decision, c.Decision)
+		})
+	}
+}
+
+func newTraceIntAttrs(attrKey string, attrValue int64) *TraceData {
+
+	return &TraceData{
+		ReceivedBatches: []consumerdata.TraceData{
+			{
+				Spans: []*tracepb.Span{
+					{
+						Attributes: &tracepb.Span_Attributes{
+							AttributeMap: map[string]*tracepb.AttributeValue{
+								attrKey: {
+									Value: &tracepb.AttributeValue_IntValue{
+										IntValue: attrValue,
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+}

processor/samplingprocessor/tailsamplingprocessor/sampling/string_tag_filter_test.go

@@ -0,0 +1,110 @@
+// 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 sampling
+
+import (
+	"testing"
+
+	commonpb "github.com/census-instrumentation/opencensus-proto/gen-go/agent/common/v1"
+	tracepb "github.com/census-instrumentation/opencensus-proto/gen-go/trace/v1"
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+	"go.uber.org/zap"
+
+	"go.opentelemetry.io/collector/consumer/consumerdata"
+)
+
+func TestStringTagFilter(t *testing.T) {
+
+	var empty = map[string]string{}
+	filter := NewStringAttributeFilter(zap.NewNop(), "example", []string{"value"})
+
+	cases := []struct {
+		Desc     string
+		Trace    *TraceData
+		Decision Decision
+	}{
+		{
+			Desc:     "nonmatching node attribute key",
+			Trace:    newTraceStringAttrs(map[string]string{"non_matching": "value"}, nil),
+			Decision: NotSampled,
+		},
+		{
+			Desc:     "nonmatching node attribute value",
+			Trace:    newTraceStringAttrs(map[string]string{"example": "non_matching"}, nil),
+			Decision: NotSampled,
+		},
+		{
+			Desc:     "matching node attribute",
+			Trace:    newTraceStringAttrs(map[string]string{"example": "value"}, nil),
+			Decision: Sampled,
+		},
+		{
+			Desc:     "nonmatching span attribute key",
+			Trace:    newTraceStringAttrs(empty, newSpan("nonmatching", "value")),
+			Decision: NotSampled,
+		},
+		{
+			Desc:     "nonmatching span attribute value",
+			Trace:    newTraceStringAttrs(empty, newSpan("example", "nonmatching")),
+			Decision: NotSampled,
+		},
+		{
+			Desc:     "matching span attribute",
+			Trace:    newTraceStringAttrs(empty, newSpan("example", "value")),
+			Decision: Sampled,
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.Desc, func(t *testing.T) {
+			u, _ := uuid.NewRandom()
+			decision, err := filter.Evaluate(u[:], c.Trace)
+			assert.NoError(t, err)
+			assert.Equal(t, decision, c.Decision)
+		})
+	}
+}
+
+func newSpan(attrKey string, attrValue string) *tracepb.Span {
+	return &tracepb.Span{
+		Attributes: &tracepb.Span_Attributes{
+			AttributeMap: map[string]*tracepb.AttributeValue{
+				attrKey: {
+					Value: &tracepb.AttributeValue_StringValue{
+						StringValue: &tracepb.TruncatableString{
+							Value: attrValue,
+						},
+					},
+				},
+			},
+		},
+	}
+}
+
+func newTraceStringAttrs(nodeAttrs map[string]string, span *tracepb.Span) *TraceData {
+	return &TraceData{
+		ReceivedBatches: []consumerdata.TraceData{
+			{
+				Node: &commonpb.Node{
+					Attributes: nodeAttrs,
+				},
+				Spans: []*tracepb.Span{
+					span,
+				},
+			},
+		},
+	}
+}