diagnostics: Add a few tests

diagnostics/collection.go

@@ -32,7 +32,8 @@ func Init(instanceID uuid.UUID) {
 	if enabled {
 		panic("already initialized")
 	}
-	if instanceID.String() == "" {
+	if str := instanceID.String(); str == "" ||
+		instanceID.String() == "00000000-0000-0000-0000-000000000000" {
 		panic("empty UUID")
 	}
 	instanceUUID = instanceID

diagnostics/collection_test.go

@@ -0,0 +1,109 @@
+// Copyright 2015 Light Code Labs, LLC
+//
+// 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 diagnostics
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/google/uuid"
+)
+
+func TestInit(t *testing.T) {
+	reset()
+
+	id := doInit(t) // should not panic
+
+	defer func() {
+		if r := recover(); r == nil {
+			t.Errorf("Second call to Init should have panicked")
+		}
+	}()
+	Init(id) // should panic
+}
+
+func TestInitEmptyUUID(t *testing.T) {
+	reset()
+	defer func() {
+		if r := recover(); r == nil {
+			t.Errorf("Call to Init with empty UUID should have panicked")
+		}
+	}()
+	Init(uuid.UUID([16]byte{}))
+}
+
+func TestSet(t *testing.T) {
+	reset()
+
+	// should be no-op since we haven't called Init() yet
+	Set("test1", "foobar")
+	if _, ok := buffer["test"]; ok {
+		t.Errorf("Should not have inserted item when not initialized")
+	}
+
+	// should work after we've initialized
+	doInit(t)
+	Set("test1", "foobar")
+	val, ok := buffer["test1"]
+	if !ok {
+		t.Errorf("Expected value to be in buffer, but it wasn't")
+	} else if val.(string) != "foobar" {
+		t.Errorf("Expected 'foobar', got '%v'", val)
+	}
+
+	// should not overfill buffer
+	maxBufferItemsTmp := maxBufferItems
+	maxBufferItems = 10
+	for i := 0; i < maxBufferItems+1; i++ {
+		Set(fmt.Sprintf("overfill_%d", i), "foobar")
+	}
+	if len(buffer) > maxBufferItems {
+		t.Errorf("Should not exceed max buffer size (%d); has %d items",
+			maxBufferItems, len(buffer))
+	}
+	maxBufferItems = maxBufferItemsTmp
+
+	// Should overwrite values
+	Set("test1", "foobar2")
+	val, ok = buffer["test1"]
+	if !ok {
+		t.Errorf("Expected value to be in buffer, but it wasn't")
+	} else if val.(string) != "foobar2" {
+		t.Errorf("Expected 'foobar2', got '%v'", val)
+	}
+}
+
+// doInit calls Init() with a valid UUID
+// and returns it.
+func doInit(t *testing.T) uuid.UUID {
+	id, err := uuid.Parse(testUUID)
+	if err != nil {
+		t.Fatalf("Could not make UUID: %v", err)
+	}
+	Init(id)
+	return id
+}
+
+// reset resets all the lovely package-level state;
+// can be used as a set up function in tests.
+func reset() {
+	instanceUUID = uuid.UUID{}
+	buffer = make(map[string]interface{})
+	bufferItemCount = 0
+	updating = false
+	enabled = false
+}
+
+const testUUID = "0b6cfa22-0d4c-11e8-b11b-7a0058e13201"

diagnostics/diagnostics.go

@@ -216,32 +216,39 @@ type Payload struct {
 	Data map[string]interface{} `json:"data,omitempty"`
 }
 
-// httpClient should be used for HTTP requests. It
-// is configured with a timeout for reliability.
-var httpClient = http.Client{Timeout: 1 * time.Minute}
+var (
+	// httpClient should be used for HTTP requests. It
+	// is configured with a timeout for reliability.
+	httpClient = http.Client{Timeout: 1 * time.Minute}
 
-// buffer holds the data that we are building up to send.
-var buffer = make(map[string]interface{})
-var bufferItemCount = 0
-var bufferMu sync.RWMutex // protects both the buffer and its count
+	// buffer holds the data that we are building up to send.
+	buffer          = make(map[string]interface{})
+	bufferItemCount = 0
+	bufferMu        sync.RWMutex // protects both the buffer and its count
 
-// updating is used to ensure only one
-// update happens at a time.
-var updating bool
-var updateMu sync.Mutex
+	// updating is used to ensure only one
+	// update happens at a time.
+	updating bool
+	updateMu sync.Mutex
 
-// updateTimer fires off the next update.
-// If no update is scheduled, this is nil.
-var updateTimer *time.Timer
-var updateTimerMu sync.Mutex
+	// updateTimer fires off the next update.
+	// If no update is scheduled, this is nil.
+	updateTimer   *time.Timer
+	updateTimerMu sync.Mutex
 
-// instanceUUID is the ID of the current instance.
-// This MUST be set to emit diagnostics.
-var instanceUUID uuid.UUID
+	// instanceUUID is the ID of the current instance.
+	// This MUST be set to emit diagnostics.
+	instanceUUID uuid.UUID
 
-// enabled indicates whether the package has
-// been initialized and can be actively used.
-var enabled bool
+	// enabled indicates whether the package has
+	// been initialized and can be actively used.
+	enabled bool
+
+	// maxBufferItems is the maximum number of items we'll allow
+	// in the buffer before we start dropping new ones, in a
+	// rough (simple) attempt to keep memory use under control.
+	maxBufferItems = 100000
+)
 
 const (
 	// endpoint is the base URL to remote diagnostics server;
@@ -255,9 +262,4 @@ const (
 	// this value should be a long duration to help alleviate
 	// extra load on the server.
 	defaultUpdateInterval = 1 * time.Hour
-
-	// maxBufferItems is the maximum number of items we'll allow
-	// in the buffer before we start dropping new ones, in a
-	// rough (simple) attempt to keep memory use under control.
-	maxBufferItems = 100000
 )

diagnostics/diagnostics_test.go

@@ -0,0 +1,59 @@
+// Copyright 2015 Light Code Labs, LLC
+//
+// 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 diagnostics
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+func TestMakePayloadAndResetBuffer(t *testing.T) {
+	reset()
+	id := doInit(t)
+
+	buffer = map[string]interface{}{
+		"foo1": "bar1",
+		"foo2": "bar2",
+	}
+	bufferItemCount = 2
+
+	payloadBytes, err := makePayloadAndResetBuffer()
+	if err != nil {
+		t.Fatalf("Error making payload bytes: %v", err)
+	}
+
+	if len(buffer) != 0 {
+		t.Errorf("Expected buffer len to be 0, got %d", len(buffer))
+	}
+	if bufferItemCount != 0 {
+		t.Errorf("Expected buffer item count to be 0, got %d", bufferItemCount)
+	}
+
+	var payload Payload
+	err = json.Unmarshal(payloadBytes, &payload)
+	if err != nil {
+		t.Fatalf("Error deserializing payload: %v", err)
+	}
+
+	if payload.InstanceID != id.String() {
+		t.Errorf("Expected instance ID to be set to '%s' but got '%s'", testUUID, payload.InstanceID)
+	}
+	if payload.Data == nil {
+		t.Errorf("Expected data to be set, but was nil")
+	}
+	if payload.Timestamp.IsZero() {
+		t.Errorf("Expected timestamp to be set, but was zero value")
+	}
+}