feat: test for the mixed policies case

Previously, we were only testing with DNS returning error, while
now we should also have a test case for when it's working given that
we're mixing tactics together now.

internal/enginenetx/bridgespolicy_test.go

@@ -76,9 +76,6 @@ func TestBridgesPolicy(t *testing.T) {
 		}
 	})
 
-	// TODO(bassosimone): we need to write better test cases for what
-	// happens when we have a mixture of tactics here.
-
 	t.Run("for the api.ooni.io domain with DNS failure", func(t *testing.T) {
 		expected := errors.New("mocked error")
 		p := &bridgesPolicy{
@@ -95,6 +92,7 @@ func TestBridgesPolicy(t *testing.T) {
 		ctx := context.Background()
 		tactics := p.LookupTactics(ctx, "api.ooni.io", "443")
 
+		// since the DNS fails, we should only see tactics generated by bridges
 		var count int
 		for tactic := range tactics {
 			count++
@@ -120,6 +118,76 @@ func TestBridgesPolicy(t *testing.T) {
 		}
 	})
 
+	t.Run("for the api.ooni.io domain with DNS success", func(t *testing.T) {
+		p := &bridgesPolicy{
+			Fallback: &dnsPolicy{
+				Logger: model.DiscardLogger,
+				Resolver: &mocks.Resolver{
+					MockLookupHost: func(ctx context.Context, domain string) ([]string, error) {
+						return []string{"130.192.91.211"}, nil
+					},
+				},
+			},
+		}
+
+		ctx := context.Background()
+		tactics := p.LookupTactics(ctx, "api.ooni.io", "443")
+
+		// since the DNS succeeds we should see bridge tactics mixed with DNS tactics
+		var (
+			bridgesCount int
+			dnsCount     int
+			overallCount int
+		)
+		for tactic := range tactics {
+			overallCount++
+
+			t.Log(overallCount, tactic)
+
+			if tactic.Port != "443" {
+				t.Fatal("the port should always be 443")
+			}
+
+			switch {
+			case overallCount == 5:
+				if tactic.Address != "130.192.91.211" {
+					t.Fatal("the host should be 130.192.91.211 for count == 5")
+				}
+
+				if tactic.SNI != "api.ooni.io" {
+					t.Fatal("we should see the `api.ooni.io` SNI on the wire for count == 5")
+				}
+
+				dnsCount++
+
+			default:
+				if tactic.Address != "162.55.247.208" {
+					t.Fatal("the host should be 162.55.247.208 for count != 5")
+				}
+
+				if tactic.SNI == "api.ooni.io" {
+					t.Fatal("we should not see the `api.ooni.io` SNI on the wire for count != 5")
+				}
+
+				bridgesCount++
+			}
+
+			if tactic.VerifyHostname != "api.ooni.io" {
+				t.Fatal("the VerifyHostname field should always be like `api.ooni.io`")
+			}
+		}
+
+		if overallCount <= 0 {
+			t.Fatal("expected to see at least one tactic")
+		}
+		if dnsCount != 1 {
+			t.Fatal("expected to see exactly one DNS based tactic")
+		}
+		if bridgesCount <= 0 {
+			t.Fatal("expected to see at least one bridge tactic")
+		}
+	})
+
 	t.Run("for test helper domains", func(t *testing.T) {
 		for _, domain := range bridgesPolicyTestHelpersDomains {
 			t.Run(domain, func(t *testing.T) {