Add test for reading artifact zips over HTTP

internal/zipartifacts/.gitignore

+/testdata

internal/zipartifacts/open_archive_test.go

+package zipartifacts
+
+import (
+	"archive/zip"
+	"context"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestOpenHTTPArchive(t *testing.T) {
+	const (
+		zipFile   = "test.zip"
+		entryName = "hello.txt"
+		contents  = "world"
+		testRoot  = "testdata/public"
+	)
+
+	require.NoError(t, os.MkdirAll(testRoot, 0755))
+	f, err := os.Create(filepath.Join(testRoot, zipFile))
+	require.NoError(t, err, "create file")
+	defer f.Close()
+
+	zw := zip.NewWriter(f)
+	w, err := zw.Create(entryName)
+	require.NoError(t, err, "create zip entry")
+	_, err = fmt.Fprint(w, contents)
+	require.NoError(t, err, "write zip entry contents")
+	require.NoError(t, zw.Close(), "close zip writer")
+	require.NoError(t, f.Close(), "close file")
+
+	srv := httptest.NewServer(http.FileServer(http.Dir(testRoot)))
+	defer srv.Close()
+
+	zr, err := OpenArchive(context.Background(), srv.URL+"/"+zipFile)
+	require.NoError(t, err, "call OpenArchive")
+	require.Len(t, zr.File, 1)
+
+	zf := zr.File[0]
+	require.Equal(t, entryName, zf.Name, "zip entry name")
+
+	entry, err := zf.Open()
+	require.NoError(t, err, "get zip entry reader")
+	defer entry.Close()
+
+	actualContents, err := ioutil.ReadAll(entry)
+	require.NoError(t, err, "read zip entry contents")
+	require.Equal(t, contents, string(actualContents), "compare zip entry contents")
+}