diff --git a/upgrade_test.go b/upgrade_test.go
new file mode 100644
index 00000000..e474cc1f
--- /dev/null
+++ b/upgrade_test.go
@@ -0,0 +1,183 @@
+package main
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestUpgrade1to2(t *testing.T) {
+	// Let's create test config
+	diskConfig := createTestDiskConfig(1)
+	oldDNSConfig := createTestDNSConfig(1)
+
+	err := upgradeSchema1to2(&diskConfig)
+	if err != nil {
+		t.Fatalf("Can't upgrade schema version from 1 to 2")
+	}
+
+	_, ok := diskConfig["coredns"]
+	if ok {
+		t.Fatalf("Core DNS config was not removed after upgrade schema version from 1 to 2")
+	}
+
+	dnsMap, ok := diskConfig["dns"]
+	if !ok {
+		t.Fatalf("No DNS config after upgrade schema version from 1 to 2")
+	}
+
+	// Cast dns configuration to map
+	newDNSConfig := make(map[string]interface{})
+	switch v := dnsMap.(type) {
+	case map[interface{}]interface{}:
+		if len(oldDNSConfig) != len(v) {
+			t.Fatalf("We loose some data")
+		}
+		for key, value := range v {
+			newDNSConfig[fmt.Sprint(key)] = value
+		}
+	default:
+		t.Fatalf("DNS configuration is not a map")
+	}
+
+	_, v, err := compareConfigs(oldDNSConfig, newDNSConfig)
+	if err != nil {
+		t.Fatalf("Wrong data %s, %s", v, err)
+	}
+}
+
+func TestUpgrade2to3(t *testing.T) {
+	// Let's create test config
+	diskConfig := createTestDiskConfig(2)
+	oldDNSConfig := createTestDNSConfig(2)
+
+	// Upgrade schema from 2 to 3
+	err := upgradeSchema2to3(&diskConfig)
+	if err != nil {
+		t.Fatalf("Can't update schema version from 2 to 3: %s", err)
+	}
+
+	// Check new schema version
+	newSchemaVersion := diskConfig["schema_version"]
+	switch v := newSchemaVersion.(type) {
+	case int:
+		if v != 3 {
+			t.Fatalf("Wrong schema version in new config file")
+		}
+	default:
+		t.Fatalf("Schema version is not an integer after update")
+	}
+
+	// Let's get new dns configuration
+	dnsMap, ok := diskConfig["dns"]
+	if !ok {
+		t.Fatalf("No dns config in new configuration")
+	}
+
+	// Cast dns configuration to map
+	newDNSConfig := make(map[string]interface{})
+	switch v := dnsMap.(type) {
+	case map[string]interface{}:
+		for key, value := range v {
+			newDNSConfig[fmt.Sprint(key)] = value
+		}
+	default:
+		t.Fatalf("DNS configuration is not a map")
+	}
+
+	// Check if bootstrap DNS becomes an array
+	bootstrapDNS := newDNSConfig["bootstrap_dns"]
+	switch v := bootstrapDNS.(type) {
+	case []string:
+		if len(v) != 1 {
+			t.Fatalf("Wrong count of bootsrap DNS servers")
+		}
+
+		if v[0] != "8.8.8.8:53" {
+			t.Fatalf("Wrong bootsrap DNS servers")
+		}
+	default:
+		t.Fatalf("Wrong type for bootsrap DNS")
+	}
+
+	// Set old value for bootstrap_dns and compare old and new configurations
+	newDNSConfig["bootstrap_dns"] = "8.8.8.8:53"
+	_, v, err := compareConfigs(oldDNSConfig, newDNSConfig)
+	if err != nil {
+		t.Fatalf("%s value is wrong: %s", v, err)
+	}
+}
+
+// TODO add comparation for all possible types
+func compareConfigs(oldConfig map[interface{}]interface{}, newConfig map[string]interface{}) (string, interface{}, error) {
+	oldConfigCasted := make(map[string]interface{})
+	for k, v := range oldConfig {
+		oldConfigCasted[fmt.Sprint(k)] = v
+	}
+
+	// Check old data and new data
+	for k, v := range newConfig {
+		switch value := v.(type) {
+		case string:
+		case int:
+			if value != oldConfigCasted[k] {
+
+			}
+		case []string:
+			for i, s := range value {
+				if oldConfigCasted[k].([]string)[i] != s {
+					return k, v, fmt.Errorf("wrong data for %s", k)
+				}
+			}
+		case bool:
+			if v != oldConfigCasted[k].(bool) {
+				return k, v, fmt.Errorf("wrong data for %s", k)
+			}
+		default:
+			return k, v, fmt.Errorf("unknown type in DNS configuration for %s", k)
+		}
+	}
+
+	return "", nil, nil
+}
+
+func createTestDiskConfig(schemaVersion int) (diskConfig map[string]interface{}) {
+	diskConfig = make(map[string]interface{})
+	diskConfig["language"] = "en"
+	diskConfig["filters"] = []filter{}
+	diskConfig["user_rules"] = []string{}
+	diskConfig["schema_version"] = schemaVersion
+	diskConfig["bind_host"] = "0.0.0.0"
+	diskConfig["bind_port"] = 80
+	diskConfig["auth_name"] = "name"
+	diskConfig["auth_pass"] = "pass"
+	dnsConfig := createTestDNSConfig(schemaVersion)
+	if schemaVersion > 1 {
+		diskConfig["dns"] = dnsConfig
+	} else {
+		diskConfig["coredns"] = dnsConfig
+	}
+	return diskConfig
+}
+
+func createTestDNSConfig(schemaVersion int) map[interface{}]interface{} {
+	dnsConfig := make(map[interface{}]interface{})
+	dnsConfig["port"] = 53
+	dnsConfig["blocked_response_ttl"] = 10
+	dnsConfig["querylog_enabled"] = true
+	dnsConfig["ratelimit"] = 20
+	dnsConfig["bootstrap_dns"] = "8.8.8.8:53"
+	if schemaVersion > 2 {
+		dnsConfig["bootstrap_dns"] = []string{"8.8.8.8:53"}
+	}
+	dnsConfig["parental_sensitivity"] = 13
+	dnsConfig["ratelimit_whitelist"] = []string{}
+	dnsConfig["upstream_dns"] = []string{"tls://1.1.1.1", "tls://1.0.0.1", "8.8.8.8"}
+	dnsConfig["filtering_enabled"] = true
+	dnsConfig["refuse_any"] = true
+	dnsConfig["parental_enabled"] = true
+	dnsConfig["bind_host"] = "0.0.0.0"
+	dnsConfig["protection_enabled"] = true
+	dnsConfig["safesearch_enabled"] = true
+	dnsConfig["safebrowsing_enabled"] = true
+	return dnsConfig
+}