Add option to pass packages to test command

README.md

@@ -15,15 +15,17 @@ go install github.com/konradreiche/coverdiff@latest
 
 ```
 Usage:
+	coverdiff test [packages]
 	coverdiff [file]
-	coverdiff test
 
 Flags:
 	-h, --help	print help text
 
 Examples:
 
-	coverdiff test
+	coverdiff test ./...
+
+	PAGER=delta coverdiff test
 
 	go test -cover -coverprofile=coverage.out
 	cat coverage.out | coverdiff

command.go

@@ -15,7 +15,8 @@ func command(stdin io.Reader, stdout io.Writer) error {
 	var fileName string
 	switch flag.CommandLine.Arg(0) {
 	case "test":
-		output, err := runGoTests()
+		packages := flag.CommandLine.Arg(1)
+		output, err := runGoTests(packages)
 		if err != nil {
 			return err
 		}
@@ -67,7 +68,7 @@ func usePager(
 	return cmd.Run()
 }
 
-func runGoTests() (*bytes.Buffer, error) {
+func runGoTests(packages string) (*bytes.Buffer, error) {
 	tempFile, err := createTempFile()
 	if err != nil {
 		return nil, err
@@ -77,7 +78,7 @@ func runGoTests() (*bytes.Buffer, error) {
 	cmd := exec.Command(
 		"go",
 		"test",
-		"./...",
+		packages,
 		"-cover",
 		"-coverprofile="+tempFile.Name(),
 	)

command_test.go

@@ -107,6 +107,7 @@ func TestCommand(t *testing.T) {
 
 	t.Run("run-go-tests", func(t *testing.T) {
 		os.Args[1] = "test"
+		os.Args[2] = "./size"
 		flag.Parse()
 
 		changeDir(t, "testdata")

help.go

@@ -8,8 +8,8 @@ import (
 const usage = `📑 coverdiff - print Go test coverage as diff
 
 Usage:
+	coverdiff test [packages]
 	coverdiff [file]
-	coverdiff test
 
 Flags:
 	-h, --help	print help text
@@ -19,9 +19,14 @@ differences directly on the terminal, similar to Go's -html option. You can
 provide the cover profile as a file, pass it through standard input, or let
 coverdiff run the Go tests.
 
+To handle larger outputs and add syntax highlighting automatically, set the
+PAGER environment variable to your preferred pager, such as delta.
+
 Examples:
 
-	coverdiff test
+	coverdiff test ./...
+
+	PAGER=delta coverdiff test
 
 	go test -cover -coverprofile=coverage.out
 	cat coverage.out | coverdiff