Add build constraints to the generated file

global_arg_test.go

@@ -0,0 +1,155 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+type buildConstraintTest struct {
+	Name          string
+	Args          []string
+	ExpectedLines []string
+}
+
+var buildConstraintTests = []buildConstraintTest{
+	{
+		Name: "single build constraint",
+		Args: []string{"-buildconstraint", "integrationtest"},
+		ExpectedLines: []string{
+			"// Code generated by \"enumer %s\"; DO NOT EDIT.",
+			"//go:build integrationtest",
+			"",
+			"package main",
+		},
+	},
+	{
+		Name: "or build constraint",
+		Args: []string{"-buildconstraint", "unittest || integrationtest"},
+		ExpectedLines: []string{
+			"// Code generated by \"enumer %s\"; DO NOT EDIT.",
+			"//go:build unittest || integrationtest",
+			"",
+			"package main",
+		},
+	},
+	{
+		Name: "multi build constraint",
+		Args: []string{"-buildconstraint", "integrationtest", "-buildconstraint", "unittest"},
+		ExpectedLines: []string{
+			"// Code generated by \"enumer %s\"; DO NOT EDIT.",
+			"//go:build integrationtest",
+			"//go:build unittest",
+			"",
+			"package main",
+		},
+	},
+	{
+		Name: "single comment",
+		Args: []string{"-comment", "Some long comment explaining what this enum is all about..."},
+		ExpectedLines: []string{
+			"// Code generated by \"enumer %s\"; DO NOT EDIT.",
+			"",
+			"// Some long comment explaining what this enum is all about...",
+			"package main",
+		},
+	},
+	{
+		Name: "multi comment",
+		Args: []string{"-comment", "Some long comment", "-comment", "explaining what", "-comment", "", "-comment", "    this enum is all about..."},
+		ExpectedLines: []string{
+			"// Code generated by \"enumer %s\"; DO NOT EDIT.",
+			"",
+			"// Some long commentexplaining what    this enum is all about...",
+			"package main",
+		},
+	},
+}
+
+func TestGlobalArgs(t *testing.T) {
+	const TypeName = "SnakeCaseValue"
+	const InputFilename = "transform_snake.go"
+	const TransformNameMethod = "SnakeCaseValue"
+
+	dir, err := ioutil.TempDir("", "stringer")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(dir)
+
+	// Create stringer in temporary directory.
+	stringer := filepath.Join(dir, fmt.Sprintf("stringer%s", GOEXE))
+	err = run("go", "build", "-o", stringer)
+	if err != nil {
+		t.Fatalf("building stringer: %s", err)
+	}
+
+	for _, test := range buildConstraintTests {
+		stringSource := filepath.Join(dir, InputFilename)
+
+		// combine arguments
+		var args []string
+		args = append(args, "-type", TypeName, "-output", stringSource, "-transform", TransformNameMethod)
+		args = append(args, test.Args...)
+		args = append(args, filepath.Join("testdata/"+InputFilename))
+
+		// Run stringer in temporary directory.
+		t.Logf("run: %s %v\n", stringer, args)
+		err = run(stringer, args...)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		actual := loadResult(t, stringSource, len(test.ExpectedLines))
+
+		if len(actual) != len(test.ExpectedLines) {
+			t.Errorf("'%s': expected at least %d line in the output but found only %d",
+				test.Name,
+				len(test.ExpectedLines),
+				len(actual),
+			)
+		}
+
+		for idx := 0; idx < len(test.ExpectedLines); idx++ {
+			expected := test.ExpectedLines[idx]
+
+			// The first line is a special case as the contents is dynamic
+			if idx == 0 {
+				expected = fmt.Sprintf(expected, strings.Join(args, " "))
+			}
+
+			if actual[idx] != expected {
+				t.Errorf("'%s': expected line %d \n\tto be  : %s\n\tbut was: %s",
+					test.Name,
+					idx,
+					expected,
+					actual[idx])
+			}
+		}
+	}
+}
+
+func loadResult(t *testing.T, filename string, lineCount int) []string {
+	fh, err := os.Open(filename)
+	if err != nil {
+		t.Fatal(err)
+		return nil
+	}
+	defer fh.Close()
+
+	lines := make([]string, 0)
+	scanner := bufio.NewScanner(fh)
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+		lineCount--
+		if lineCount <= 0 {
+			break
+		}
+	}
+
+	return lines
+}

stringer.go

@@ -59,9 +59,11 @@ var (
 )
 
 var comments arrayFlags
+var buildConstraints arrayFlags
 
 func init() {
 	flag.Var(&comments, "comment", "comments to include in generated code, can repeat. Default: \"\"")
+	flag.Var(&buildConstraints, "buildconstraint", "build constraint to include in the generated code, can repeat. Default: <none>")
 }
 
 // Usage is a replacement usage function for the flags package.
@@ -112,6 +114,12 @@ func main() {
 
 	// Print the header and package clause.
 	g.Printf("// Code generated by \"enumer %s\"; DO NOT EDIT.\n", strings.Join(os.Args[1:], " "))
+	if len(buildConstraints) > 0 {
+		for _, c := range buildConstraints {
+			g.Printf("//go:build %s\n", c)
+		}
+	}
+
 	g.Printf("\n")
 	if comments.String() != "" {
 		g.Printf("// %s\n", comments.String())