refactor: interfaces and data types into the model package (#642)

## Checklist

- [x] I have read the [contribution guidelines](https://github.com/ooni/probe-cli/blob/master/CONTRIBUTING.md)
- [x] reference issue for this pull request: https://github.com/ooni/probe/issues/1885
- [x] related ooni/spec pull request: N/A

Location of the issue tracker: https://github.com/ooni/probe

## Description

This PR contains a set of changes to move important interfaces and data types into the `./internal/model` package.

The criteria for including an interface or data type in here is roughly that the type should be important and used by several packages. We are especially interested to move more interfaces here to increase modularity.

An additional side effect is that, by reading this package, one should be able to understand more quickly how different parts of the codebase interact with each other.

This is what I want to move in `internal/model`:

- [x] most important interfaces from `internal/netxlite`
- [x] everything that was previously part of `internal/engine/model`
- [x] mocks from `internal/netxlite/mocks` should also be moved in here as a subpackage

internal/engine/probeservices/probeservices_test.go

@@ -13,9 +13,9 @@ import (
 	"github.com/apex/log"
 	"github.com/google/go-cmp/cmp"
 	"github.com/ooni/probe-cli/v3/internal/engine/mockable"
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
 	"github.com/ooni/probe-cli/v3/internal/engine/probeservices"
 	"github.com/ooni/probe-cli/v3/internal/engine/probeservices/testorchestra"
+	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
 )
 
@@ -25,7 +25,7 @@ func newclient() *probeservices.Client {
 			MockableHTTPClient: http.DefaultClient,
 			MockableLogger:     log.Log,
 		},
-		model.Service{
+		model.OOAPIService{
 			Address: "https://ams-pg-test.ooni.org/",
 			Type:    "https",
 		},
@@ -38,7 +38,7 @@ func newclient() *probeservices.Client {
 
 func TestNewClientHTTPS(t *testing.T) {
 	client, err := probeservices.NewClient(
-		&mockable.Session{}, model.Service{
+		&mockable.Session{}, model.OOAPIService{
 			Address: "https://x.org",
 			Type:    "https",
 		})
@@ -52,7 +52,7 @@ func TestNewClientHTTPS(t *testing.T) {
 
 func TestNewClientUnsupportedEndpoint(t *testing.T) {
 	client, err := probeservices.NewClient(
-		&mockable.Session{}, model.Service{
+		&mockable.Session{}, model.OOAPIService{
 			Address: "https://x.org",
 			Type:    "onion",
 		})
@@ -66,7 +66,7 @@ func TestNewClientUnsupportedEndpoint(t *testing.T) {
 
 func TestNewClientCloudfrontInvalidURL(t *testing.T) {
 	client, err := probeservices.NewClient(
-		&mockable.Session{}, model.Service{
+		&mockable.Session{}, model.OOAPIService{
 			Address: "\t\t\t",
 			Type:    "cloudfront",
 		})
@@ -80,7 +80,7 @@ func TestNewClientCloudfrontInvalidURL(t *testing.T) {
 
 func TestNewClientCloudfrontInvalidURLScheme(t *testing.T) {
 	client, err := probeservices.NewClient(
-		&mockable.Session{}, model.Service{
+		&mockable.Session{}, model.OOAPIService{
 			Address: "http://x.org",
 			Type:    "cloudfront",
 		})
@@ -94,7 +94,7 @@ func TestNewClientCloudfrontInvalidURLScheme(t *testing.T) {
 
 func TestNewClientCloudfrontInvalidURLWithPort(t *testing.T) {
 	client, err := probeservices.NewClient(
-		&mockable.Session{}, model.Service{
+		&mockable.Session{}, model.OOAPIService{
 			Address: "https://x.org:54321",
 			Type:    "cloudfront",
 		})
@@ -108,7 +108,7 @@ func TestNewClientCloudfrontInvalidURLWithPort(t *testing.T) {
 
 func TestNewClientCloudfrontInvalidFront(t *testing.T) {
 	client, err := probeservices.NewClient(
-		&mockable.Session{}, model.Service{
+		&mockable.Session{}, model.OOAPIService{
 			Address: "https://x.org",
 			Type:    "cloudfront",
 			Front:   "\t\t\t",
@@ -123,7 +123,7 @@ func TestNewClientCloudfrontInvalidFront(t *testing.T) {
 
 func TestNewClientCloudfrontGood(t *testing.T) {
 	client, err := probeservices.NewClient(
-		&mockable.Session{}, model.Service{
+		&mockable.Session{}, model.OOAPIService{
 			Address: "https://x.org",
 			Type:    "cloudfront",
 			Front:   "google.com",
@@ -144,7 +144,7 @@ func TestCloudfront(t *testing.T) {
 		t.Skip("skip test in short mode")
 	}
 	client, err := probeservices.NewClient(
-		&mockable.Session{}, model.Service{
+		&mockable.Session{}, model.OOAPIService{
 			Address: "https://meek.azureedge.net",
 			Type:    "cloudfront",
 			Front:   "ajax.aspnetcdn.com",
@@ -197,7 +197,7 @@ func TestDefaultProbeServicesWorkAsIntended(t *testing.T) {
 }
 
 func TestSortEndpoints(t *testing.T) {
-	in := []model.Service{{
+	in := []model.OOAPIService{{
 		Type:    "onion",
 		Address: "httpo://jehhrikjjqrlpufu.onion",
 	}, {
@@ -208,7 +208,7 @@ func TestSortEndpoints(t *testing.T) {
 		Type:    "https",
 		Address: "https://ams-ps2.ooni.nu:443",
 	}}
-	expect := []model.Service{{
+	expect := []model.OOAPIService{{
 		Type:    "https",
 		Address: "https://ams-ps2.ooni.nu:443",
 	}, {
@@ -227,7 +227,7 @@ func TestSortEndpoints(t *testing.T) {
 }
 
 func TestOnlyHTTPS(t *testing.T) {
-	in := []model.Service{{
+	in := []model.OOAPIService{{
 		Type:    "onion",
 		Address: "httpo://jehhrikjjqrlpufu.onion",
 	}, {
@@ -244,7 +244,7 @@ func TestOnlyHTTPS(t *testing.T) {
 		Type:    "https",
 		Address: "https://mia-ps-nonexistent.ooni.io",
 	}}
-	expect := []model.Service{{
+	expect := []model.OOAPIService{{
 		Type:    "https",
 		Address: "https://ams-ps-nonexistent.ooni.io",
 	}, {
@@ -263,7 +263,7 @@ func TestOnlyHTTPS(t *testing.T) {
 
 func TestOnlyFallbacks(t *testing.T) {
 	// put onion first so we also verify that we sort the endpoints
-	in := []model.Service{{
+	in := []model.OOAPIService{{
 		Type:    "onion",
 		Address: "httpo://jehhrikjjqrlpufu.onion",
 	}, {
@@ -280,7 +280,7 @@ func TestOnlyFallbacks(t *testing.T) {
 		Type:    "https",
 		Address: "https://mia-ps-nonexistent.ooni.io",
 	}}
-	expect := []model.Service{{
+	expect := []model.OOAPIService{{
 		Front:   "dkyhjv0wpi2dk.cloudfront.net",
 		Type:    "cloudfront",
 		Address: "https://dkyhjv0wpi2dk.cloudfront.net",
@@ -297,7 +297,7 @@ func TestOnlyFallbacks(t *testing.T) {
 
 func TestTryAllCanceledContext(t *testing.T) {
 	// put onion first so we also verify that we sort the endpoints
-	in := []model.Service{{
+	in := []model.OOAPIService{{
 		Type:    "onion",
 		Address: "httpo://jehhrikjjqrlpufu.onion",
 	}, {
@@ -401,7 +401,7 @@ func TestTryAllIntegrationWeRaceForFastestHTTPS(t *testing.T) {
 	}
 	const pattern = "^https://ps[1-4].ooni.io$"
 	// put onion first so we also verify that we sort the endpoints
-	in := []model.Service{{
+	in := []model.OOAPIService{{
 		Type:    "onion",
 		Address: "httpo://jehhrikjjqrlpufu.onion",
 	}, {
@@ -472,7 +472,7 @@ func TestTryAllIntegrationWeFallback(t *testing.T) {
 		t.Skip("skip test in short mode")
 	}
 	// put onion first so we also verify that we sort the endpoints
-	in := []model.Service{{
+	in := []model.OOAPIService{{
 		Type:    "onion",
 		Address: "httpo://jehhrikjjqrlpufu.onion",
 	}, {
@@ -573,32 +573,32 @@ func TestSelectBestOnlyFailures(t *testing.T) {
 func TestSelectBestSelectsTheFastest(t *testing.T) {
 	in := []*probeservices.Candidate{{
 		Duration: 10 * time.Millisecond,
-		Endpoint: model.Service{
+		Endpoint: model.OOAPIService{
 			Address: "https://ps1.ooni.io",
 			Type:    "https",
 		},
 	}, {
 		Duration: 4 * time.Millisecond,
-		Endpoint: model.Service{
+		Endpoint: model.OOAPIService{
 			Address: "https://ps2.ooni.io",
 			Type:    "https",
 		},
 	}, {
 		Duration: 7 * time.Millisecond,
-		Endpoint: model.Service{
+		Endpoint: model.OOAPIService{
 			Address: "https://ps3.ooni.io",
 			Type:    "https",
 		},
 	}, {
 		Duration: 11 * time.Millisecond,
-		Endpoint: model.Service{
+		Endpoint: model.OOAPIService{
 			Address: "https://ps4.ooni.io",
 			Type:    "https",
 		},
 	}}
 	expected := &probeservices.Candidate{
 		Duration: 4 * time.Millisecond,
-		Endpoint: model.Service{
+		Endpoint: model.OOAPIService{
 			Address: "https://ps2.ooni.io",
 			Type:    "https",
 		},