Test the observation example in Go

examples/go-library/observe/main.go

@@ -158,13 +158,16 @@ func run() (summary, error) {
 }
 
 func main() {
-	value, err := run()
-	if err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
-	}
-	if err := json.NewEncoder(os.Stdout).Encode(value); err != nil {
+	if err := execute(os.Stdout); err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)
 	}
 }
+
+func execute(out io.Writer) error {
+	value, err := run()
+	if err != nil {
+		return err
+	}
+	return json.NewEncoder(out).Encode(value)
+}

examples/go-library/observe/main_test.go

@@ -0,0 +1,30 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"testing"
+)
+
+func TestObserveExample(t *testing.T) {
+	var output bytes.Buffer
+	if err := execute(&output); err != nil {
+		t.Fatal(err)
+	}
+	var got struct {
+		ProposalAttempts   *int   `json:"proposal_attempts"`
+		ProposalRetries    *int   `json:"proposal_transient_retries"`
+		UsageComplete      *bool  `json:"proposal_usage_complete"`
+		AssessmentAttempts *int   `json:"assessment_attempts"`
+		AssessmentRetries  *int   `json:"assessment_transient_retries"`
+		Outcome            string `json:"assessment_outcome"`
+	}
+	if err := json.Unmarshal(output.Bytes(), &got); err != nil {
+		t.Fatal(err)
+	}
+	if got.ProposalAttempts == nil || *got.ProposalAttempts != 2 || got.ProposalRetries == nil || *got.ProposalRetries != 1 ||
+		got.UsageComplete == nil || *got.UsageComplete || got.AssessmentAttempts == nil || *got.AssessmentAttempts != 1 ||
+		got.AssessmentRetries == nil || *got.AssessmentRetries != 0 || got.Outcome != "accepted" {
+		t.Fatalf("unexpected observation summary: %+v", got)
+	}
+}