Add coverage for ls command

integration/common/basesuites.go

@@ -3,6 +3,7 @@
 package common
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"path"
@@ -120,3 +121,15 @@ func (s *BaseSuite) TestLocalOutputTarBuild() {
 	require.NoError(s.T(), err, "build failed")
 	// TODO - consider inspecting the out.tar for validity...
 }
+
+func (s *BaseSuite) TestLs() {
+	buf := &bytes.Buffer{}
+	err := RunBuildkit("ls", []string{}, RunBuildStreams{Out: buf})
+	require.NoError(s.T(), err, "%s: ls failed", s.Name)
+	lines := buf.String()
+	require.Contains(s.T(), lines, s.Name)
+
+	err = RunBuildkit("ls", []string{"dummy"}, RunBuildStreams{})
+	require.Error(s.T(), err)
+	require.Contains(s.T(), err.Error(), "requires exactly")
+}

pkg/cmd/ls.go

@@ -4,7 +4,6 @@ package commands
 
 import (
 	"fmt"
-	"os"
 	"strings"
 	"text/tabwriter"
 
@@ -35,7 +34,7 @@ func runLs(streams genericclioptions.IOStreams, in lsOptions) error {
 		builders = append(builders, b...)
 	}
 
-	w := tabwriter.NewWriter(os.Stdout, 0, 0, 1, ' ', 0)
+	w := tabwriter.NewWriter(streams.Out, 0, 0, 1, ' ', 0)
 	fmt.Fprintf(w, "NAME\tNODE\tDRIVER\tSTATUS\tPLATFORMS\n")
 
 	for _, b := range builders {