Add a test for create command flag handling.

This complements the fix in 705865fa by adding a test for unset flags
with defaults as well as other combinations of set and unset flags.

Signed-off-by: John Sirois <john.sirois@gmail.com>

commands/create_test.go

@@ -3,6 +3,9 @@ package commands
 import (
 	"testing"
 
+	"flag"
+	"github.com/docker/machine/commands/commandstest"
+	"github.com/docker/machine/libmachine/mcnflag"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -20,3 +23,97 @@ func TestValidateSwarmDiscoveryAcceptsValidFormat(t *testing.T) {
 	err := validateSwarmDiscovery("token://deadbeefcafe")
 	assert.NoError(t, err)
 }
+
+type fakeFlagGetter struct {
+	flag.Value
+	value interface{}
+}
+
+func (ff fakeFlagGetter) Get() interface{} {
+	return ff.value
+}
+
+var nilStringSlice []string
+
+var getDriverOptsFlags = []mcnflag.Flag{
+	mcnflag.BoolFlag{
+		Name: "bool",
+	},
+	mcnflag.IntFlag{
+		Name: "int",
+	},
+	mcnflag.IntFlag{
+		Name:  "int_defaulted",
+		Value: 42,
+	},
+	mcnflag.StringFlag{
+		Name: "string",
+	},
+	mcnflag.StringFlag{
+		Name:  "string_defaulted",
+		Value: "bob",
+	},
+	mcnflag.StringSliceFlag{
+		Name: "stringslice",
+	},
+	mcnflag.StringSliceFlag{
+		Name:  "stringslice_defaulted",
+		Value: []string{"joe"},
+	},
+}
+
+var getDriverOptsTests = []struct {
+	data     map[string]interface{}
+	expected map[string]interface{}
+}{
+	{
+		expected: map[string]interface{}{
+			"bool":                  false,
+			"int":                   0,
+			"int_defaulted":         42,
+			"string":                "",
+			"string_defaulted":      "bob",
+			"stringslice":           nilStringSlice,
+			"stringslice_defaulted": []string{"joe"},
+		},
+	},
+	{
+		data: map[string]interface{}{
+			"bool":             fakeFlagGetter{value: true},
+			"int":              fakeFlagGetter{value: 42},
+			"int_defaulted":    fakeFlagGetter{value: 37},
+			"string":           fakeFlagGetter{value: "jake"},
+			"string_defaulted": fakeFlagGetter{value: "george"},
+			// NB: StringSlices are not flag.Getters.
+			"stringslice":           []string{"ford"},
+			"stringslice_defaulted": []string{"zaphod", "arthur"},
+		},
+		expected: map[string]interface{}{
+			"bool":                  true,
+			"int":                   42,
+			"int_defaulted":         37,
+			"string":                "jake",
+			"string_defaulted":      "george",
+			"stringslice":           []string{"ford"},
+			"stringslice_defaulted": []string{"zaphod", "arthur"},
+		},
+	},
+}
+
+func TestGetDriverOpts(t *testing.T) {
+	for _, tt := range getDriverOptsTests {
+		commandLine := &commandstest.FakeCommandLine{
+			LocalFlags: &commandstest.FakeFlagger{
+				Data: tt.data,
+			},
+		}
+		driverOpts := getDriverOpts(commandLine, getDriverOptsFlags)
+		assert.Equal(t, tt.expected["bool"], driverOpts.Bool("bool"))
+		assert.Equal(t, tt.expected["int"], driverOpts.Int("int"))
+		assert.Equal(t, tt.expected["int_defaulted"], driverOpts.Int("int_defaulted"))
+		assert.Equal(t, tt.expected["string"], driverOpts.String("string"))
+		assert.Equal(t, tt.expected["string_defaulted"], driverOpts.String("string_defaulted"))
+		assert.Equal(t, tt.expected["stringslice"], driverOpts.StringSlice("stringslice"))
+		assert.Equal(t, tt.expected["stringslice_defaulted"], driverOpts.StringSlice("stringslice_defaulted"))
+	}
+}