Follow up work on docker_log input (#6008)

internal/docker/docker_test.go

@@ -0,0 +1,59 @@
+package docker_test
+
+import (
+	"testing"
+
+	"github.com/influxdata/telegraf/internal/docker"
+	"github.com/stretchr/testify/require"
+)
+
+func TestParseImage(t *testing.T) {
+	tests := []struct {
+		image         string
+		parsedName    string
+		parsedVersion string
+	}{
+		{
+			image:         "postgres",
+			parsedName:    "postgres",
+			parsedVersion: "unknown",
+		},
+		{
+			image:         "postgres:latest",
+			parsedName:    "postgres",
+			parsedVersion: "latest",
+		},
+		{
+			image:         "coreos/etcd",
+			parsedName:    "coreos/etcd",
+			parsedVersion: "unknown",
+		},
+		{
+			image:         "coreos/etcd:latest",
+			parsedName:    "coreos/etcd",
+			parsedVersion: "latest",
+		},
+		{
+			image:         "quay.io/postgres",
+			parsedName:    "quay.io/postgres",
+			parsedVersion: "unknown",
+		},
+		{
+			image:         "quay.io:4443/coreos/etcd",
+			parsedName:    "quay.io:4443/coreos/etcd",
+			parsedVersion: "unknown",
+		},
+		{
+			image:         "quay.io:4443/coreos/etcd:latest",
+			parsedName:    "quay.io:4443/coreos/etcd",
+			parsedVersion: "latest",
+		},
+	}
+	for _, tt := range tests {
+		t.Run("parse name "+tt.image, func(t *testing.T) {
+			imageName, imageVersion := docker.ParseImage(tt.image)
+			require.Equal(t, tt.parsedName, imageName)
+			require.Equal(t, tt.parsedVersion, imageVersion)
+		})
+	}
+}