diff --git a/agent/agent.go b/agent/agent.go
index 2687bbc0f..e6e982c02 100644
--- a/agent/agent.go
+++ b/agent/agent.go
@@ -136,7 +136,7 @@ func (a *Agent) Run(ctx context.Context) error {
 }
 
 // Test runs the inputs once and prints the output to stdout in line protocol.
-func (a *Agent) Test(ctx context.Context) error {
+func (a *Agent) Test(ctx context.Context, waitDuration time.Duration) error {
 	var wg sync.WaitGroup
 	metricC := make(chan telegraf.Metric)
 	nulC := make(chan telegraf.Metric)
@@ -156,8 +156,8 @@ func (a *Agent) Test(ctx context.Context) error {
 			octets, err := s.Serialize(metric)
 			if err == nil {
 				fmt.Print("> ", string(octets))
-
 			}
+			metric.Reject()
 		}
 	}()
 
@@ -168,43 +168,61 @@ func (a *Agent) Test(ctx context.Context) error {
 		}
 	}()
 
+	hasServiceInputs := false
+	for _, input := range a.Config.Inputs {
+		if _, ok := input.Input.(telegraf.ServiceInput); ok {
+			hasServiceInputs = true
+			break
+		}
+	}
+
+	if hasServiceInputs {
+		log.Printf("D! [agent] Starting service inputs")
+		err := a.startServiceInputs(ctx, metricC)
+		if err != nil {
+			return err
+		}
+	}
+
 	for _, input := range a.Config.Inputs {
 		select {
 		case <-ctx.Done():
 			return nil
 		default:
-			if _, ok := input.Input.(telegraf.ServiceInput); ok {
-				log.Printf("W!: [agent] skipping plugin [[%s]]: service inputs not supported in --test mode",
-					input.Name())
-				continue
+			break
+		}
+
+		acc := NewAccumulator(input, metricC)
+		acc.SetPrecision(a.Precision())
+
+		// Special instructions for some inputs. cpu, for example, needs to be
+		// run twice in order to return cpu usage percentages.
+		switch input.Name() {
+		case "inputs.cpu", "inputs.mongodb", "inputs.procstat":
+			nulAcc := NewAccumulator(input, nulC)
+			nulAcc.SetPrecision(a.Precision())
+			if err := input.Input.Gather(nulAcc); err != nil {
+				acc.AddError(err)
 			}
 
-			acc := NewAccumulator(input, metricC)
-			acc.SetPrecision(a.Precision())
-			input.SetDefaultTags(a.Config.Tags)
-
-			// Special instructions for some inputs. cpu, for example, needs to be
-			// run twice in order to return cpu usage percentages.
-			switch input.Name() {
-			case "inputs.cpu", "inputs.mongodb", "inputs.procstat":
-				nulAcc := NewAccumulator(input, nulC)
-				nulAcc.SetPrecision(a.Precision())
-				if err := input.Input.Gather(nulAcc); err != nil {
-					return err
-				}
-
-				time.Sleep(500 * time.Millisecond)
-				if err := input.Input.Gather(acc); err != nil {
-					return err
-				}
-			default:
-				if err := input.Input.Gather(acc); err != nil {
-					return err
-				}
+			time.Sleep(500 * time.Millisecond)
+			if err := input.Input.Gather(acc); err != nil {
+				acc.AddError(err)
+			}
+		default:
+			if err := input.Input.Gather(acc); err != nil {
+				acc.AddError(err)
 			}
 		}
 	}
 
+	if hasServiceInputs {
+		log.Printf("D! [agent] Waiting for service inputs")
+		internal.SleepContext(ctx, waitDuration)
+		log.Printf("D! [agent] Stopping service inputs")
+		a.stopServiceInputs()
+	}
+
 	return nil
 }
 
diff --git a/cmd/telegraf/telegraf.go b/cmd/telegraf/telegraf.go
index 3678387cd..4545833a7 100644
--- a/cmd/telegraf/telegraf.go
+++ b/cmd/telegraf/telegraf.go
@@ -13,6 +13,7 @@ import (
 	"runtime"
 	"strings"
 	"syscall"
+	"time"
 
 	"github.com/influxdata/telegraf/agent"
 	"github.com/influxdata/telegraf/internal"
@@ -33,7 +34,8 @@ var pprofAddr = flag.String("pprof-addr", "",
 	"pprof address to listen on, not activate pprof if empty")
 var fQuiet = flag.Bool("quiet", false,
 	"run in quiet mode")
-var fTest = flag.Bool("test", false, "gather metrics, print them out, and exit")
+var fTest = flag.Bool("test", false, "enable test mode: gather metrics, print them out, and exit")
+var fTestWait = flag.Int("test-wait", 0, "wait up to this many seconds for service inputs to complete in test mode")
 var fConfig = flag.String("config", "", "configuration file to load")
 var fConfigDirectory = flag.String("config-directory", "",
 	"directory containing additional *.conf files")
@@ -167,8 +169,9 @@ func runAgent(ctx context.Context,
 
 	logger.SetupLogging(logConfig)
 
-	if *fTest {
-		return ag.Test(ctx)
+	if *fTest || *fTestWait != 0 {
+		testWaitDuration := time.Duration(*fTestWait) * time.Second
+		return ag.Test(ctx, testWaitDuration)
 	}
 
 	log.Printf("I! Loaded inputs: %s", strings.Join(c.InputNames(), " "))
diff --git a/internal/usage.go b/internal/usage.go
index c783da3f4..7909d3558 100644
--- a/internal/usage.go
+++ b/internal/usage.go
@@ -31,6 +31,8 @@ The commands & flags are:
   --sample-config                print out full sample configuration
   --test                         gather metrics, print them out, and exit;
                                  processors, aggregators, and outputs are not run
+  --test-wait                    wait up to this many seconds for service
+                                 inputs to complete in test mode
   --usage <plugin>               print usage for a plugin, ie, 'telegraf --usage mysql'
   --version                      display the version and exit
 
diff --git a/internal/usage_windows.go b/internal/usage_windows.go
index 6e3c17835..af2506ec1 100644
--- a/internal/usage_windows.go
+++ b/internal/usage_windows.go
@@ -31,6 +31,8 @@ The commands & flags are:
                                  'processors', 'aggregators' and 'inputs'
   --test                         gather metrics, print them out, and exit;
                                  processors, aggregators, and outputs are not run
+  --test-wait                    wait up to this many seconds for service
+                                 inputs to complete in test mode
   --usage <plugin>               print usage for a plugin, ie, 'telegraf --usage mysql'
   --version                      display the version and exit