refactor: add support for mage and golangci-lint

.golangci.yaml

@@ -0,0 +1,29 @@
+---
+run:
+  concurrency: 2
+  timeout: 1m
+  issues-exit-code: 1
+  tests: true
+
+output:
+  format: colored-line-number
+  print-issues-lines: true
+  print-linter-name: true
+  uniq-by-line: true
+  sort-results: true
+
+linters:
+  enable-all: true
+  # disable:
+  fast: false
+
+linters-settings:
+  lll:
+    line-length: 140
+
+issues:
+  exclude-rules:
+  - path: greet_test.go
+    linters:
+    - ifshort
+    - testpackage

go.mod

@@ -1,3 +1,5 @@
 module forge.dananglin.me.uk/code/dananglin/greet
 
 go 1.17
+
+require github.com/magefile/mage v1.11.0

go.sum

@@ -0,0 +1,2 @@
+github.com/magefile/mage v1.11.0 h1:C/55Ywp9BpgVVclD3lRnSYCwXTYxmSppIgLeDYlNuls=
+github.com/magefile/mage v1.11.0/go.mod h1:z5UZb/iS3GoOSn0JgWuiw7dxlurVYTu+/jHXqQg881A=

greet.go

@@ -2,15 +2,24 @@ package main
 
 import (
 	"fmt"
-	"os"
 	"io"
+	"log"
+	"os"
 )
 
+type numberOfArgumentError struct {
+	length int
+}
+
+func (e numberOfArgumentError) Error() string {
+	return fmt.Sprintf("unexpected number of arguments passed to the greeter: want 0 or 1 argument, got %d", e.length)
+}
+
 func main() {
 	osArgs := os.Args[1:]
 
 	if err := greet(os.Stdout, osArgs); err != nil {
-		fmt.Printf("ERROR: %s.\n", err)
+		log.Fatalf("ERROR: %s.\n", err)
 	}
 }
 
@@ -18,8 +27,10 @@ func greet(w io.Writer, n []string) error {
 	var name string
 
 	if len(n) > 1 {
-		return fmt.Errorf("unexpected number of arguments passed to the greeter: want 0 or 1 argument, got %d", len(n))
-	} else if len(n) == 0 {
+		return numberOfArgumentError{length: len(n)}
+	}
+
+	if len(n) == 0 {
 		name = "World"
 	} else {
 		name = n[0]

greet_test.go

@@ -7,14 +7,17 @@ import (
 
 // TestGreetNoArguments tests the greeter's response when given no names.
 func TestGreetNoArguments(t *testing.T) {
+	t.Parallel()
+
 	buffer := new(bytes.Buffer)
 	args := make([]string, 0)
 
 	if err := greet(buffer, args); err != nil {
-		t.Fatalf("an error occured while running greet(): %s", err)
+		t.Fatalf("an error occurred while running greet(): %s", err)
 	}
 
 	want := "Hello, World!\n"
+
 	got := buffer.String()
 
 	if want != got {
@@ -26,14 +29,17 @@ func TestGreetNoArguments(t *testing.T) {
 
 // TestGreetOneArgument tests the greeter's response when given one name.
 func TestGreetOneArgument(t *testing.T) {
+	t.Parallel()
+
 	buffer := new(bytes.Buffer)
 	args := []string{"Sarah"}
 
 	if err := greet(buffer, args); err != nil {
-		t.Fatalf("an error occured while running greet(): %s", err)
+		t.Fatalf("an error occurred while running greet(): %s", err)
 	}
 
 	want := "Hello, Sarah!\n"
+
 	got := buffer.String()
 
 	if want != got {
@@ -45,17 +51,19 @@ func TestGreetOneArgument(t *testing.T) {
 
 // TestGreetTwoArguments tests the greeter's response when given two names.
 func TestGreetTwoArguments(t *testing.T) {
+	t.Parallel()
+
 	buffer := new(bytes.Buffer)
 	args := []string{"Bob", "John"}
 
-	want := "unexpected number of arguments passed to the greeter: want 0 or 1 argument, got 2"
-	
 	err := greet(buffer, args)
 
 	if err == nil {
 		t.Error("unexpected nil error returned.")
 	}
 
+	want := "unexpected number of arguments passed to the greeter: want 0 or 1 argument, got 2"
+
 	got := err.Error()
 
 	if want != got {

magefile.go

@@ -0,0 +1,59 @@
+//go:build mage
+// +build mage
+
+package main
+
+import (
+	"os"
+
+	"github.com/magefile/mage/sh"
+)
+
+const (
+	binary = "greet"
+)
+
+var Default = Build
+
+// Test run the go tests
+// To enable verbose mode set PELICAN_TEST_VERBOSE=1.
+// To enable coverage mode set PELICAN_TEST_COVER=1.
+func Test() error {
+	goTest := sh.RunCmd("go", "test")
+
+	args := []string{"."}
+
+	if os.Getenv("GO_TEST_VERBOSE") == "1" {
+		args = append(args, "-v")
+	}
+
+	if os.Getenv("GO_TEST_COVER") == "1" {
+		args = append(args, "-cover")
+	}
+
+	return goTest(args...)
+}
+
+// Lint runs golangci-lint against the code.
+func Lint() error {
+	return sh.RunV("golangci-lint", "run", "--color", "always")
+}
+
+// Build build the executable
+func Build() error {
+	main := "greet.go"
+	return sh.Run("go", "build", "-o", binary, main)
+}
+
+// Clean clean the workspace
+func Clean() error {
+	if err := sh.Rm(binary); err != nil {
+		return err
+	}
+
+	if err := sh.Run("go", "clean", "."); err != nil {
+		return err
+	}
+
+	return nil
+}