Skip mitm for unsupported registries (#185)

* implement mitm decider for npm

* fix: Skip MITM for registries not supported for analysis

proxy/interceptors/pypi_registry_test.go

@@ -0,0 +1,31 @@
+package interceptors
+
+import (
+	"testing"
+
+	"github.com/safedep/pmg/proxy"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPypiRegistryInterceptor_ShouldMITM(t *testing.T) {
+	interceptor := NewPypiRegistryInterceptor(nil, nil, nil, nil)
+
+	tests := []struct {
+		name     string
+		hostname string
+		wantMITM bool
+	}{
+		{"pypi files is MITM'd", "files.pythonhosted.org", true},
+		{"pypi org is MITM'd", "pypi.org", true},
+		{"test pypi is NOT MITM'd", "test.pypi.org", false},
+		{"test pypi files is NOT MITM'd", "test-files.pythonhosted.org", false},
+		{"unknown registry is NOT MITM'd", "registry.example.com", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ctx := &proxy.RequestContext{Hostname: tt.hostname}
+			assert.Equal(t, tt.wantMITM, interceptor.ShouldMITM(ctx))
+		})
+	}
+}