tests: Include UT tests to pkg/api/download

Add unit tests for `pkg/api/download` coverage as 85%

Signed-off-by: Kairo de Araujo <kairo.araujo@testifysec.com>

pkg/api/download.go

@@ -56,7 +56,7 @@ func DownloadWithWriter(ctx context.Context, baseUrl, gitoid string, dst io.Writ
 	hc := &http.Client{}
 	resp, err := hc.Do(req)
 	if err != nil {
-		return nil
+		return err
 	}
 
 	defer resp.Body.Close()

pkg/api/download_test.go

@@ -0,0 +1,172 @@
+// Copyright 2023 The Archivista Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package api_test
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path"
+	"testing"
+
+	"github.com/in-toto/archivista/pkg/api"
+	"github.com/in-toto/go-witness/dsse"
+	"github.com/stretchr/testify/suite"
+)
+
+// Test Suite: UT APIDownload
+type UTAPIDownloadSuite struct {
+	suite.Suite
+}
+
+func TestAPIDownloadSuite(t *testing.T) {
+	suite.Run(t, new(UTAPIDownloadSuite))
+}
+
+func (ut *UTAPIDownloadSuite) Test_Download() {
+
+	testEnvelope, err := os.ReadFile("../../test/package.attestation.json")
+	if err != nil {
+		ut.FailNow(err.Error())
+	}
+	expectedEnvelop := dsse.Envelope{}
+	err = json.Unmarshal(testEnvelope, &expectedEnvelop)
+	if err != nil {
+		ut.FailNow(err.Error())
+	}
+
+	testServer := httptest.NewServer(
+		http.HandlerFunc(
+			func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(http.StatusOK)
+				_, err = w.Write(testEnvelope)
+				if err != nil {
+					ut.FailNow(err.Error())
+				}
+			},
+		),
+	)
+	defer testServer.Close()
+	ctx := context.TODO()
+
+	// test api.Download happy flow
+	resp, err := api.Download(ctx, testServer.URL, "gitoid_test")
+	if err != nil {
+		ut.FailNow(err.Error())
+	}
+
+	ut.Equal(expectedEnvelop, resp)
+}
+
+func (ut *UTAPIDownloadSuite) Test_Download_DecodeFailure() {
+	testServer := httptest.NewServer(
+		http.HandlerFunc(
+			func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(http.StatusOK)
+				_, err := w.Write([]byte(`invalid`))
+				if err != nil {
+					ut.FailNow(err.Error())
+				}
+			},
+		),
+	)
+	defer testServer.Close()
+	ctx := context.TODO()
+
+	// test api.Download happy flow
+	resp, err := api.Download(ctx, testServer.URL, "gitoid_test")
+	ut.Error(err)
+	ut.Equal(dsse.Envelope{}, resp)
+}
+
+func (ut *UTAPIDownloadSuite) Test_DownloadWithReader() {
+
+	// mock server
+	expected := `{"body":"body"}`
+	testServer := httptest.NewServer(
+		http.HandlerFunc(
+			func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(http.StatusOK)
+				_, err := w.Write([]byte(expected))
+				if err != nil {
+					ut.FailNow(err.Error())
+				}
+			},
+		),
+	)
+	defer testServer.Close()
+
+	// context
+	ctx := context.TODO()
+
+	// temporary file
+	tempDir := os.TempDir()
+	dst, err := os.Create(path.Join(tempDir, "test"))
+	if err != nil {
+		ut.FailNow(err.Error())
+	}
+	err = api.DownloadWithWriter(ctx, testServer.URL, "gitoid", dst)
+	if err != nil {
+		ut.FailNow(err.Error())
+	}
+
+	// validate result
+	result, err := os.ReadFile(path.Join(tempDir, "test"))
+	if err != nil {
+		ut.FailNow(err.Error())
+	}
+	ut.Equal(expected, string(result))
+}
+
+func (ut *UTAPIDownloadSuite) Test_DownloadWithWriter_NoServer() {
+
+	// context
+	ctx := context.TODO()
+
+	// dst as stdout
+	var dst io.Writer = os.Stdout
+
+	err := api.DownloadWithWriter(ctx, "http://invalid-archivista", "gitoid_test", dst)
+	ut.ErrorContains(err, "dial tcp: lookup invalid-archivista: no such host")
+}
+
+func (ut *UTAPIDownloadSuite) Test_DownloadWithWriter_BadStatusCode() {
+
+	// mock server
+	testServer := httptest.NewServer(
+		http.HandlerFunc(
+			func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(http.StatusInternalServerError)
+				_, err := w.Write([]byte(`Internal Server Error`))
+				if err != nil {
+					ut.FailNow(err.Error())
+				}
+			},
+		),
+	)
+	defer testServer.Close()
+
+	// dst as stdout
+	var dst io.Writer = os.Stdout
+
+	// context
+	ctx := context.TODO()
+
+	err := api.DownloadWithWriter(ctx, testServer.URL, "gitoid_test", dst)
+	ut.ErrorContains(err, "Internal Server Error")
+}