Sorts credentials alphabetically before prompting

Signed-off-by: Urvashi Reddy <[email protected]>

cmd/duffle/credential_generate.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"io/ioutil"
 	"path/filepath"
+	"sort"
 	"strings"
 
 	"github.com/spf13/cobra"
@@ -114,7 +115,14 @@ func genCredentialSet(name string, creds map[string]bundle.Location, fn credenti
 		return cs, fmt.Errorf("credentialset name '%s' cannot contain the following characters: './\\'", name)
 	}
 
+	var credentialNames []string
 	for name := range creds {
+		credentialNames = append(credentialNames, name)
+	}
+
+	sort.Strings(credentialNames)
+
+	for _, name := range credentialNames {
 		c, err := fn(name)
 		if err != nil {
 			return cs, err

cmd/duffle/credential_generate_test.go

@@ -18,21 +18,28 @@ func TestGenCredentialSet(t *testing.T) {
 			EnvironmentVariable: "SECOND_VAR",
 			Path:                "/second/path",
 		},
+		"third": {
+			Path: "/third/path",
+		},
 	}
 	is := assert.New(t)
 	creds, err := genCredentialSet(name, credlocs, genEmptyCredentials)
 	is.NoError(err)
 	is.Equal(creds.Name, name)
-	is.Len(creds.Credentials, 2)
+	is.Len(creds.Credentials, 3)
 
-	found := map[string]bool{"first": false, "second": false}
+	found := map[string]bool{"first": false, "second": false, "third": false}
 
+	var assignmentOrder []string
 	for _, cred := range creds.Credentials {
+		assignmentOrder = append(assignmentOrder, cred.Name)
 		found[cred.Name] = true
 		is.Equal(cred.Source.Value, "EMPTY")
 	}
 
-	is.Len(found, 2)
+	is.Equal([]string{"first", "second", "third"}, assignmentOrder)
+
+	is.Len(found, 3)
 	for k, v := range found {
 		is.True(v, "%q not found", k)
 	}