refactor: make internals easier to test and add unit tests (#2)

This PR refactors most of the internals to make them easier to test (and also because the names didn't make sense). It adds unit tests for all internal components.

Reviewed-on: #2
Co-authored-by: Emmanuel BENOÎT <tseeker@nocternity.net>
Co-committed-by: Emmanuel BENOÎT <tseeker@nocternity.net>

cmd/sslcert/main.go

@@ -16,7 +16,7 @@ import (
 
 	"nocternity.net/gomonop/pkg/perfdata"
 	"nocternity.net/gomonop/pkg/plugin"
-	"nocternity.net/gomonop/pkg/program"
+	"nocternity.net/gomonop/pkg/results"
 )
 
 //--------------------------------------------------------------------------------------------------------
@@ -167,7 +167,7 @@ type programFlags struct {
 // Program data including configuration and runtime data.
 type checkProgram struct {
 	programFlags                   // Flags from the command line
-	plugin       *plugin.Plugin    // Plugin output state
+	plugin       *results.Results  // Plugin output state
 	certificate  *x509.Certificate // X.509 certificate from the server
 }
 
@@ -207,37 +207,37 @@ func (flags *programFlags) parseArguments() {
 }
 
 // Initialise the monitoring check program.
-func NewProgram() program.Program {
+func NewProgram() plugin.Plugin {
 	program := &checkProgram{
-		plugin: plugin.New("Certificate check"),
+		plugin: results.New("Certificate check"),
 	}
 	program.parseArguments()
 	return program
 }
 
-// Terminate the monitoring check program.
-func (program *checkProgram) Done() {
-	program.plugin.Done()
+// Return the program's output value.
+func (program *checkProgram) Results() *results.Results {
+	return program.plugin
 }
 
 // Check the values that were specified from the command line. Returns true
 // if the arguments made sense.
 func (program *checkProgram) CheckArguments() bool {
 	if program.hostname == "" {
-		program.plugin.SetState(plugin.UNKNOWN, "no hostname specified")
+		program.plugin.SetState(results.StatusUnknown, "no hostname specified")
 		return false
 	}
 	if program.port < 1 || program.port > 65535 {
-		program.plugin.SetState(plugin.UNKNOWN, "invalid or missing port number")
+		program.plugin.SetState(results.StatusUnknown, "invalid or missing port number")
 		return false
 	}
 	if program.warn != -1 && program.crit != -1 && program.warn <= program.crit {
-		program.plugin.SetState(plugin.UNKNOWN, "nonsensical thresholds")
+		program.plugin.SetState(results.StatusUnknown, "nonsensical thresholds")
 		return false
 	}
 	if _, ok := certGetters[program.startTLS]; !ok {
 		errstr := "unsupported StartTLS protocol " + program.startTLS
-		program.plugin.SetState(plugin.UNKNOWN, errstr)
+		program.plugin.SetState(results.StatusUnknown, errstr)
 		return false
 	}
 	program.hostname = strings.ToLower(program.hostname)
@@ -262,13 +262,13 @@ func (program *checkProgram) getCertificate() error {
 // matches the requested host name.
 func (program *checkProgram) checkSANlessCertificate() bool {
 	if !program.ignoreCnOnly || len(program.extraNames) != 0 {
-		program.plugin.SetState(plugin.WARNING,
+		program.plugin.SetState(results.StatusWarning,
 			"certificate doesn't have SAN domain names")
 		return false
 	}
 	dn := strings.ToLower(program.certificate.Subject.String())
 	if !strings.HasPrefix(dn, fmt.Sprintf("cn=%s,", program.hostname)) {
-		program.plugin.SetState(plugin.CRITICAL, "incorrect certificate CN")
+		program.plugin.SetState(results.StatusCritical, "incorrect certificate CN")
 		return false
 	}
 	return true
@@ -298,7 +298,7 @@ func (program *checkProgram) checkNames() bool {
 		certificateIsOk = program.checkHostName(name) && certificateIsOk
 	}
 	if !certificateIsOk {
-		program.plugin.SetState(plugin.CRITICAL, "names missing from SAN domain names")
+		program.plugin.SetState(results.StatusCritical, "names missing from SAN domain names")
 	}
 	return certificateIsOk
 }
@@ -306,26 +306,26 @@ func (program *checkProgram) checkNames() bool {
 // Check a certificate's time to expiry against the warning and critical
 // thresholds, returning a status code and description based on these
 // values.
-func (program *checkProgram) checkCertificateExpiry(tlDays int) (plugin.Status, string) {
+func (program *checkProgram) checkCertificateExpiry(tlDays int) (results.Status, string) {
 	if tlDays <= 0 {
-		return plugin.CRITICAL, "certificate expired"
+		return results.StatusCritical, "certificate expired"
 	}
 
 	var limitStr string
-	var state plugin.Status
+	var state results.Status
 
 	switch {
 	case program.crit > 0 && tlDays <= program.crit:
 		limitStr = fmt.Sprintf(" (<= %d)", program.crit)
-		state = plugin.CRITICAL
+		state = results.StatusCritical
 
 	case program.warn > 0 && tlDays <= program.warn:
 		limitStr = fmt.Sprintf(" (<= %d)", program.warn)
-		state = plugin.WARNING
+		state = results.StatusWarning
 
 	default:
 		limitStr = ""
-		state = plugin.OK
+		state = results.StatusOK
 	}
 
 	statusString := fmt.Sprintf("certificate will expire in %d days%s",
@@ -338,10 +338,10 @@ func (program *checkProgram) checkCertificateExpiry(tlDays int) (plugin.Status,
 func (program *checkProgram) setPerfData(tlDays int) {
 	pdat := perfdata.New("validity", perfdata.UomNone, strconv.Itoa(tlDays))
 	if program.crit > 0 {
-		pdat.SetCrit(perfdata.PDRMax(strconv.Itoa(program.crit)))
+		pdat.SetCrit(perfdata.RangeMax(strconv.Itoa(program.crit)))
 	}
 	if program.warn > 0 {
-		pdat.SetWarn(perfdata.PDRMax(strconv.Itoa(program.warn)))
+		pdat.SetWarn(perfdata.RangeMax(strconv.Itoa(program.warn)))
 	}
 	program.plugin.AddPerfData(pdat)
 }
@@ -351,7 +351,7 @@ func (program *checkProgram) setPerfData(tlDays int) {
 func (program *checkProgram) RunCheck() {
 	err := program.getCertificate()
 	if err != nil {
-		program.plugin.SetState(plugin.UNKNOWN, err.Error())
+		program.plugin.SetState(results.StatusUnknown, err.Error())
 	} else if program.checkNames() {
 		timeLeft := time.Until(program.certificate.NotAfter)
 		tlDays := int((timeLeft + 86399*time.Second) / (24 * time.Hour))

cmd/zoneserial/main.go

@@ -14,7 +14,7 @@ import (
 
 	"nocternity.net/gomonop/pkg/perfdata"
 	"nocternity.net/gomonop/pkg/plugin"
-	"nocternity.net/gomonop/pkg/program"
+	"nocternity.net/gomonop/pkg/results"
 )
 
 //-------------------------------------------------------------------------------------------------------
@@ -55,8 +55,8 @@ type programFlags struct {
 
 // Program data including configuration and runtime data.
 type checkProgram struct {
-	programFlags                // Flags from the command line
-	plugin       *plugin.Plugin // Plugin output state
+	programFlags                  // Flags from the command line
+	plugin       *results.Results // Plugin output state
 }
 
 // Parse command line arguments and store their values. If the -h flag is present,
@@ -77,43 +77,39 @@ func (flags *programFlags) parseArguments() {
 }
 
 // Initialise the monitoring check program.
-func NewProgram() program.Program {
+func NewProgram() plugin.Plugin {
 	program := &checkProgram{
-		plugin: plugin.New("DNS zone serial match check"),
+		plugin: results.New("DNS zone serial match check"),
 	}
 	program.parseArguments()
 	return program
 }
 
-// Terminate the monitoring check program.
-func (program *checkProgram) Done() {
-	if r := recover(); r != nil {
-		program.plugin.SetState(plugin.UNKNOWN, "Internal error")
-		program.plugin.AddLinef("Error info: %v", r)
-	}
-	program.plugin.Done()
+// Return the program's output value.
+func (program *checkProgram) Results() *results.Results {
+	return program.plugin
 }
 
 // Check the values that were specified from the command line. Returns true if the arguments made sense.
 func (program *checkProgram) CheckArguments() bool {
 	if program.hostname == "" {
-		program.plugin.SetState(plugin.UNKNOWN, "no DNS hostname specified")
+		program.plugin.SetState(results.StatusUnknown, "no DNS hostname specified")
 		return false
 	}
 	if program.port < 1 || program.port > 65535 {
-		program.plugin.SetState(plugin.UNKNOWN, "invalid DNS port number")
+		program.plugin.SetState(results.StatusUnknown, "invalid DNS port number")
 		return false
 	}
 	if program.zone == "" {
-		program.plugin.SetState(plugin.UNKNOWN, "no DNS zone specified")
+		program.plugin.SetState(results.StatusUnknown, "no DNS zone specified")
 		return false
 	}
 	if program.rsHostname == "" {
-		program.plugin.SetState(plugin.UNKNOWN, "no reference DNS hostname specified")
+		program.plugin.SetState(results.StatusUnknown, "no reference DNS hostname specified")
 		return false
 	}
 	if program.rsPort < 1 || program.rsPort > 65535 {
-		program.plugin.SetState(plugin.UNKNOWN, "invalid reference DNS port number")
+		program.plugin.SetState(results.StatusUnknown, "invalid reference DNS port number")
 		return false
 	}
 	program.hostname = strings.ToLower(program.hostname)
@@ -180,12 +176,12 @@ func (program *checkProgram) RunCheck() {
 	cOk, cSerial := program.getSerial("checked", checkResponse)
 	rOk, rSerial := program.getSerial("reference", refResponse)
 	if !(cOk && rOk) {
-		program.plugin.SetState(plugin.UNKNOWN, "could not read serials")
+		program.plugin.SetState(results.StatusUnknown, "could not read serials")
 		return
 	}
 	if cSerial == rSerial {
-		program.plugin.SetState(plugin.OK, "serials match")
+		program.plugin.SetState(results.StatusOK, "serials match")
 	} else {
-		program.plugin.SetState(plugin.CRITICAL, "serials mismatch")
+		program.plugin.SetState(results.StatusCritical, "serials mismatch")
 	}
 }

go.mod

@@ -8,7 +8,11 @@ require (
 )
 
 require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/stretchr/testify v1.9.0 // indirect
 	golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550 // indirect
 	golang.org/x/net v0.0.0-20190923162816-aa69164e4478 // indirect
 	golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,7 +1,13 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/karrick/golf v1.4.0 h1:9i9HnUh7uCyUFJhIqg311HBibw4f2pbGldi0ZM2FhaQ=
 github.com/karrick/golf v1.4.0/go.mod h1:qGN0IhcEL+IEgCXp00RvH32UP59vtwc8w5YcIdArNRk=
 github.com/miekg/dns v1.1.40 h1:pyyPFfGMnciYUk/mXpKkVmeMQjfXqt3FAJ2hy7tPiLA=
 github.com/miekg/dns v1.1.40/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550 h1:ObdrDkeb4kJdCP557AjRjq69pTHfNouLtWZG7j9rPN8=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
@@ -19,3 +25,6 @@ golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/tools v0.0.0-20191216052735-49a3e744a425/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

main.go

@@ -7,33 +7,34 @@ import (
 
 	"nocternity.net/gomonop/cmd/sslcert"
 	"nocternity.net/gomonop/cmd/zoneserial"
-	"nocternity.net/gomonop/pkg/program"
+	"nocternity.net/gomonop/pkg/plugin"
+	"nocternity.net/gomonop/pkg/results"
 	"nocternity.net/gomonop/pkg/version"
 )
 
 var (
-	programs map[string]program.Builder = map[string]program.Builder{
+	plugins map[string]plugin.Builder = map[string]plugin.Builder{
 		"check_ssl_certificate": sslcert.NewProgram,
 		"check_zone_serial":     zoneserial.NewProgram,
 	}
 )
 
-func getProgram() program.Program {
+func getPlugin() plugin.Plugin {
 	ownName := filepath.Base(os.Args[0])
 
-	if builder, ok := programs[ownName]; ok {
+	if builder, ok := plugins[ownName]; ok {
 		return builder()
 	}
 
 	if len(os.Args) < 2 {
-		fmt.Printf("Syntax: %s <program> [arguments]\n", ownName)
-		fmt.Printf("        %s --programs|-p\n", ownName)
+		fmt.Printf("Syntax: %s <plugin> [arguments]\n", ownName)
+		fmt.Printf("        %s --plugin|-p\n", ownName)
 		fmt.Printf("        %s --version|-v", ownName)
 	}
 
 	switch os.Args[1] {
-	case "--programs", "-p":
-		for name := range programs {
+	case "--plugins", "-p":
+		for name := range plugins {
 			fmt.Println(name)
 		}
 		os.Exit(0)
@@ -43,20 +44,30 @@ func getProgram() program.Program {
 		os.Exit(0)
 	}
 
-	if builder, ok := programs[os.Args[1]]; ok {
+	if builder, ok := plugins[os.Args[1]]; ok {
 		os.Args = os.Args[1:]
 		return builder()
 	}
 
-	fmt.Printf("Unknown program: %s\n", os.Args[1])
+	fmt.Printf("Unknown plugin: %s\n", os.Args[1])
 	os.Exit(1)
 	return nil
 }
 
 func main() {
-	program := getProgram()
-	defer program.Done()
-	if program.CheckArguments() {
-		program.RunCheck()
+	runPlugin := getPlugin()
+
+	output := runPlugin.Results()
+	defer func() {
+		if r := recover(); r != nil {
+			output.SetState(results.StatusUnknown, "Internal error")
+			output.AddLinef("Error info: %v", r)
+		}
+		fmt.Println(output.String())
+		os.Exit(output.ExitCode())
+	}()
+
+	if runPlugin.CheckArguments() {
+		runPlugin.RunCheck()
 	}
 }

pkg/perfdata/internals.go

@@ -0,0 +1,25 @@
+package perfdata // import nocternity.net/gomonop/pkg/perfdata
+
+import (
+	"regexp"
+)
+
+// Flags indicating which elements of performance data have been set.
+type perfDataBits int
+
+const (
+	PDatWarn perfDataBits = 1 << iota
+	PDatCrit
+	PDatMin
+	PDatMax
+)
+
+// Regexps used to check values and ranges in performance data records.
+var (
+	// Common value check regexp.
+	vcRegexp = `^-?(0(\.\d*)?|[1-9]\d*(\.\d*)?|\.\d+)$`
+	// Compiled value check regexp.
+	valueCheck = regexp.MustCompile(vcRegexp)
+	// Compiled range min value check.
+	rangeMinCheck = regexp.MustCompile(vcRegexp + `|^~$`)
+)

pkg/perfdata/internals_test.go

@@ -0,0 +1,50 @@
+package perfdata // import nocternity.net/gomonop/pkg/perfdata
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestValueCheckValid(t *testing.T) {
+	validValues := []string{
+		"0", "0.", "0.952", "1", "123", "123.", "123.45", ".1",
+		"-0", "-0.", "-0.952", "-1", "-123", "-123.", "-123.45", "-.1",
+	}
+
+	for _, value := range validValues {
+		assert.True(t, valueCheck.MatchString(value), "'%s' is a valid value string", value)
+	}
+}
+
+func TestValueCheckInvalid(t *testing.T) {
+	invalidValues := []string{".", "-.", "a", " ", "", "~"}
+
+	for _, value := range invalidValues {
+		assert.False(t, valueCheck.MatchString(value), "'%s' is an invalid value string", value)
+	}
+}
+
+func TestMinCheckValid(t *testing.T) {
+	validValues := []string{
+		"0", "0.", "0.952", "1", "123", "123.", "123.45", ".1",
+		"-0", "-0.", "-0.952", "-1", "-123", "-123.", "-123.45", "-.1",
+		"~",
+	}
+
+	for _, value := range validValues {
+		if !rangeMinCheck.MatchString(value) {
+			t.Errorf("'%s' is a valid value string", value)
+		}
+	}
+}
+
+func TestMinCheckInvalid(t *testing.T) {
+	invalidValues := []string{".", "-.", "a", " ", ""}
+
+	for _, value := range invalidValues {
+		if rangeMinCheck.MatchString(value) {
+			t.Errorf("'%s' is an invalid value string", value)
+		}
+	}
+}

pkg/perfdata/perfdata.go

@@ -3,111 +3,9 @@
 package perfdata // import nocternity.net/gomonop/pkg/perfdata
 
 import (
-	"fmt"
-	"regexp"
 	"strings"
 )
 
-// Units of measurement, which may be used to qualify the performance data.
-type UnitOfMeasurement int
-
-const (
-	UomNone UnitOfMeasurement = iota
-	UomSeconds
-	UomPercent
-	UomBytes
-	UomKilobytes
-	UomMegabytes
-	UomGigabytes
-	UomTerabytes
-	UomCounter
-)
-
-func (u UnitOfMeasurement) String() string {
-	return [...]string{"", "s", "%", "B", "KB", "MB", "GB", "TB", "c"}[u]
-}
-
-// Flags indicating which elements of performance data have been set.
-type perfDataBits int
-
-const (
-	PDatWarn perfDataBits = 1 << iota
-	PDatCrit
-	PDatMin
-	PDatMax
-)
-
-// Regexps used to check values and ranges in performance data records.
-var (
-	// Common value check regexp.
-	vcRegexp = `^-?(0(\.\d*)?|[1-9]\d*(\.\d*)?|\.\d+)$`
-	// Compiled value check regexp.
-	valueCheck = regexp.MustCompile(vcRegexp)
-	// Compiled range min value check.
-	rangeMinCheck = regexp.MustCompile(vcRegexp + `|^~$`)
-)
-
-// Performance data range.
-type PDRange struct {
-	start  string
-	end    string
-	inside bool
-}
-
-// Creates a performance data range from -inf to 0 and from the specified
-// value to +inf.
-func PDRMax(max string) *PDRange {
-	if !valueCheck.MatchString(max) {
-		panic("invalid performance data range maximum value")
-	}
-	pdRange := &PDRange{}
-	pdRange.start = "0"
-	pdRange.end = max
-	return pdRange
-}
-
-// Creates a performance data range from -inf to the specified minimal value
-// and from the specified maximal value to +inf.
-func PDRMinMax(min, max string) *PDRange {
-	if !valueCheck.MatchString(max) {
-		panic("invalid performance data range maximum value")
-	}
-	if !rangeMinCheck.MatchString(min) {
-		panic("invalid performance data range minimum value")
-	}
-	pdRange := &PDRange{}
-	pdRange.start = min
-	pdRange.end = max
-	return pdRange
-}
-
-// Inverts the range.
-func (r *PDRange) Inside() *PDRange {
-	r.inside = true
-	return r
-}
-
-// Generates the range's string representation so it can be sent to the
-// monitoring system.
-func (r *PDRange) String() string {
-	var start, inside string
-
-	switch r.start {
-	case "":
-		start = "~"
-	case "0":
-		start = ""
-	default:
-		start = r.start
-	}
-
-	if r.inside {
-		inside = "@"
-	}
-
-	return inside + start + ":" + r.end
-}
-
 // Performance data, including a label, units, a value, warning/critical
 // ranges and min/max boundaries.
 type PerfData struct {
@@ -115,7 +13,7 @@ type PerfData struct {
 	units      UnitOfMeasurement
 	bits       perfDataBits
 	value      string
-	warn, crit PDRange
+	warn, crit Range
 	min, max   string
 }
 
@@ -136,13 +34,13 @@ func New(label string, units UnitOfMeasurement, value string) *PerfData {
 }
 
 // Set the warning range for the performance data record.
-func (d *PerfData) SetWarn(r *PDRange) {
+func (d *PerfData) SetWarn(r *Range) {
 	d.warn = *r
 	d.bits |= PDatWarn
 }
 
 // Set the critical range for the performance data record.
-func (d *PerfData) SetCrit(r *PDRange) {
+func (d *PerfData) SetCrit(r *Range) {
 	d.crit = *r
 	d.bits |= PDatCrit
 }
@@ -171,26 +69,28 @@ func (d *PerfData) String() string {
 	var strBuilder strings.Builder
 	needsQuotes := strings.ContainsAny(d.Label, " '=\"")
 	if needsQuotes {
-		strBuilder.WriteString("'")
+		strBuilder.WriteRune('\'')
 	}
 	strBuilder.WriteString(strings.ReplaceAll(d.Label, "'", "''"))
 	if needsQuotes {
-		strBuilder.WriteString("'")
+		strBuilder.WriteRune('\'')
 	}
-	strBuilder.WriteString("=")
-	strBuilder.WriteString(fmt.Sprintf("%s%s;", d.value, d.units.String()))
+	strBuilder.WriteRune('=')
+	strBuilder.WriteString(d.value)
+	strBuilder.WriteString(d.units.String())
+	strBuilder.WriteRune(';')
 	if d.bits&PDatWarn != 0 {
 		strBuilder.WriteString(d.warn.String())
 	}
-	strBuilder.WriteString(";")
+	strBuilder.WriteRune(';')
 	if d.bits&PDatCrit != 0 {
 		strBuilder.WriteString(d.crit.String())
 	}
-	strBuilder.WriteString(";")
+	strBuilder.WriteRune(';')
 	if d.bits&PDatMin != 0 {
 		strBuilder.WriteString(d.min)
 	}
-	strBuilder.WriteString(";")
+	strBuilder.WriteRune(';')
 	if d.bits&PDatMax != 0 {
 		strBuilder.WriteString(d.max)
 	}

pkg/perfdata/perfdata_test.go

@@ -1,108 +1,261 @@
-package perfdata // import nocternity.net/gomonop/pkg/perfdata
+package perfdata
 
 import (
 	"fmt"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
-func assert(t *testing.T, check bool, msg string) {
-	if !check {
-		t.Errorf(msg)
-	}
+func TestNewNoValue(t *testing.T) {
+	const label = "label"
+	const units = UomNone
+
+	out := New(label, units, "")
+
+	assert.Equal(t, label, out.Label)
+	assert.Equal(t, units, out.units)
+	assert.Equal(t, perfDataBits(0), out.bits)
+	assert.Equal(t, "U", out.value)
+	// min, max, warn and crit are meaningless here
 }
 
-func assertPanic(t *testing.T, f func(), msg string) {
-	defer func() {
-		if r := recover(); r == nil {
-			t.Errorf(msg)
-		}
-	}()
-	f()
+func TestNewValidValue(t *testing.T) {
+	const label = "label"
+	const units = UomNone
+	const value = "1234"
+
+	out := New(label, units, value)
+
+	assert.Equal(t, label, out.Label)
+	assert.Equal(t, units, out.units)
+	assert.Equal(t, perfDataBits(0), out.bits)
+	assert.Equal(t, value, out.value)
+	// min, max, warn and crit are meaningless here
 }
 
-func TestValueCheckValid(t *testing.T) {
-	validValues := []string{
-		"0", "0.", "0.952", "1", "123", "123.", "123.45", ".1",
-		"-0", "-0.", "-0.952", "-1", "-123", "-123.", "-123.45", "-.1",
-	}
-
-	for _, value := range validValues {
-		if !valueCheck.MatchString(value) {
-			t.Errorf("'%s' is a valid value string", value)
-		}
-	}
+func TestNewInvalidValue(t *testing.T) {
+	assert.Panics(t, func() { New("label", UomNone, "nope") })
 }
 
-func TestValueCheckInvalid(t *testing.T) {
-	invalidValues := []string{".", "-.", "a", " ", ""}
+func TestSetWarn(t *testing.T) {
+	rangeValue := Range{start: "A", end: "B"}
+	rangeStr := rangeValue.String()
 
-	for _, value := range invalidValues {
-		if valueCheck.MatchString(value) {
-			t.Errorf("'%s' is an invalid value string", value)
-		}
-	}
+	data := PerfData{}
+	data.SetWarn(&rangeValue)
+
+	assert.True(t, data.bits&PDatWarn != 0)
+	assert.Equal(t, rangeStr, data.warn.String())
 }
 
-func TestPdrMaxInvalid(t *testing.T) {
-	assertPanic(
-		t, func() { PDRMax("") },
-		"Created PerfDataRange with invalid max value",
-	)
+func TestSetWarnTwice(t *testing.T) {
+	range1Value := Range{start: "A", end: "B"}
+	range2Value := Range{start: "C", end: "D"}
+	range2Str := range2Value.String()
+	require.NotEqual(t, range2Str, range1Value.String())
+
+	data := PerfData{}
+	data.SetWarn(&range1Value)
+	data.SetWarn(&range2Value)
+
+	assert.True(t, data.bits&PDatWarn != 0)
+	assert.Equal(t, range2Str, data.warn.String())
 }
 
-func TestPdrMax(t *testing.T) {
-	value := "123"
-	pdr := PDRMax(value)
-	assert(t, pdr.start == "0", "Min value should be '0'")
-	assert(t, pdr.end == value, "Max value not copied to PerfDataRange")
-	assert(t, !pdr.inside, "Inside flag should not be set")
+func TestSetCrit(t *testing.T) {
+	rangeValue := Range{start: "A", end: "B"}
+	rangeStr := rangeValue.String()
+
+	data := PerfData{}
+	data.SetCrit(&rangeValue)
+
+	assert.True(t, data.bits&PDatCrit != 0)
+	assert.Equal(t, rangeStr, data.crit.String())
 }
 
-func TestPdrMinMaxInvalid(t *testing.T) {
-	assertPanic(
-		t, func() { PDRMinMax("", "123") },
-		"Created PerfDataRange with invalid min value",
-	)
-	assertPanic(
-		t, func() { PDRMinMax("123", "") },
-		"Created PerfDataRange with invalid max value",
-	)
+func TestSetCritTwice(t *testing.T) {
+	range1Value := Range{start: "A", end: "B"}
+	range2Value := Range{start: "C", end: "D"}
+	range2Str := range2Value.String()
+	require.NotEqual(t, range2Str, range1Value.String())
+
+	data := PerfData{}
+	data.SetCrit(&range1Value)
+	data.SetCrit(&range2Value)
+
+	assert.True(t, data.bits&PDatCrit != 0)
+	assert.Equal(t, range2Str, data.crit.String())
 }
 
-func TestPdrMinMax(t *testing.T) {
-	min, max := "123", "456"
-	pdr := PDRMinMax(min, max)
-	assert(t, pdr.start == min, "Min value not copied to PerfDataRange")
-	assert(t, pdr.end == max, "Max value not copied to PerfDataRange")
-	assert(t, !pdr.inside, "Inside flag should not be set")
+func TestSetMin(t *testing.T) {
+	const min = "100"
+
+	data := PerfData{}
+	data.SetMin(min)
+
+	assert.True(t, data.bits&PDatMin != 0)
+	assert.Equal(t, min, data.min)
 }
 
-func TestPdrInside(t *testing.T) {
-	pdr := &PDRange{}
-	pdr = pdr.Inside()
-	assert(t, pdr.inside, "Inside flag should be set")
-	pdr = pdr.Inside()
-	assert(t, pdr.inside, "Inside flag should still be set")
+func TestSetMinInvalid(t *testing.T) {
+	data := PerfData{}
+	assert.Panics(t, func() { data.SetMin("nope") })
 }
 
-func TestPdrString(t *testing.T) {
+func TestSetMinTwice(t *testing.T) {
+	data := PerfData{}
+	data.SetMin("100")
+	data.SetMin("200")
+	assert.Equal(t, "200", data.min)
+	assert.True(t, data.bits&PDatMin != 0)
+}
+
+func TestSetMax(t *testing.T) {
+	const max = "100"
+
+	data := PerfData{}
+	data.SetMax(max)
+
+	assert.True(t, data.bits&PDatMax != 0)
+	assert.Equal(t, max, data.max)
+}
+
+func TestSetMaxInvalid(t *testing.T) {
+	data := PerfData{}
+	assert.Panics(t, func() { data.SetMax("nope") })
+}
+
+func TestSetMaxTwice(t *testing.T) {
+	data := PerfData{}
+	data.SetMax("100")
+	data.SetMax("200")
+	assert.Equal(t, "200", data.max)
+	assert.True(t, data.bits&PDatMax != 0)
+}
+
+func TestString(t *testing.T) {
 	type Test struct {
-		pdr PDRange
-		out string
+		PerfData
+		expected string
 	}
+
+	range1 := Range{start: "A", end: "B"}
+	range2 := Range{start: "C", end: "D"}
+
 	tests := []Test{
-		{pdr: PDRange{start: "Y", end: "X"}, out: "Y:X"},
-		{pdr: PDRange{end: "X"}, out: "~:X"},
-		{pdr: PDRange{start: "0", end: "X"}, out: ":X"},
-		{pdr: PDRange{inside: true, start: "Y", end: "X"}, out: "@Y:X"},
+		{
+			PerfData{
+				Label: "label",
+				units: UomNone,
+				bits:  perfDataBits(0),
+				value: "1234",
+			},
+			"label=1234;;;;",
+		},
+		{
+			PerfData{
+				Label: "la=bel",
+				units: UomNone,
+				bits:  perfDataBits(0),
+				value: "1234",
+			},
+			"'la=bel'=1234;;;;",
+		},
+		{
+			PerfData{
+				Label: "la bel",
+				units: UomNone,
+				bits:  perfDataBits(0),
+				value: "1234",
+			},
+			"'la bel'=1234;;;;",
+		},
+		{
+			PerfData{
+				Label: "la\"bel",
+				units: UomNone,
+				bits:  perfDataBits(0),
+				value: "1234",
+			},
+			"'la\"bel'=1234;;;;",
+		},
+		{
+			PerfData{
+				Label: "la'bel",
+				units: UomNone,
+				bits:  perfDataBits(0),
+				value: "1234",
+			},
+			"'la''bel'=1234;;;;",
+		},
+		{
+			PerfData{
+				Label: "label",
+				units: UomNone,
+				bits:  PDatWarn,
+				value: "1234",
+				warn:  range1,
+			},
+			"label=1234;" + range1.String() + ";;;",
+		},
+		{
+			PerfData{
+				Label: "label",
+				units: UomNone,
+				bits:  PDatCrit,
+				value: "1234",
+				crit:  range1,
+			},
+			"label=1234;;" + range1.String() + ";;",
+		},
+		{
+			PerfData{
+				Label: "label",
+				units: UomNone,
+				bits:  PDatWarn | PDatCrit,
+				value: "1234",
+				warn:  range1,
+				crit:  range2,
+			},
+			"label=1234;" + range1.String() + ";" + range2.String() + ";;",
+		},
+		{
+			PerfData{
+				Label: "label",
+				units: UomNone,
+				bits:  PDatMin,
+				value: "1234",
+				min:   "X",
+			},
+			"label=1234;;;X;",
+		},
+		{
+			PerfData{
+				Label: "label",
+				units: UomNone,
+				bits:  PDatMax,
+				value: "1234",
+				max:   "Y",
+			},
+			"label=1234;;;;Y",
+		},
+	}
+
+	for _, units := range []UnitOfMeasurement{UomSeconds, UomPercent, UomBytes, UomKilobytes, UomMegabytes, UomGigabytes, UomTerabytes, UomCounter} {
+		tests = append(tests, Test{
+			PerfData{
+				Label: "label",
+				units: units,
+				bits:  perfDataBits(0),
+				value: "1234",
+			},
+			fmt.Sprintf("label=1234%s;;;;", units),
+		})
 	}
 
 	for _, test := range tests {
-		result := test.pdr.String()
-		assert(
-			t,
-			result == test.out,
-			fmt.Sprintf("Expected '%s', got '%s'", test.out, result),
-		)
+		assert.Equal(t, test.expected, test.PerfData.String())
 	}
 }

pkg/perfdata/range.go

@@ -0,0 +1,62 @@
+package perfdata // import nocternity.net/gomonop/pkg/perfdata
+
+// Performance data range.
+type Range struct {
+	start  string
+	end    string
+	inside bool
+}
+
+// Creates a performance data range from -inf to 0 and from the specified
+// value to +inf.
+func RangeMax(max string) *Range {
+	if !valueCheck.MatchString(max) {
+		panic("invalid performance data range maximum value")
+	}
+	pdRange := &Range{}
+	pdRange.start = "0"
+	pdRange.end = max
+	return pdRange
+}
+
+// Creates a performance data range from -inf to the specified minimal value
+// and from the specified maximal value to +inf.
+func RangeMinMax(min, max string) *Range {
+	if !valueCheck.MatchString(max) {
+		panic("invalid performance data range maximum value")
+	}
+	if !rangeMinCheck.MatchString(min) {
+		panic("invalid performance data range minimum value")
+	}
+	pdRange := &Range{}
+	pdRange.start = min
+	pdRange.end = max
+	return pdRange
+}
+
+// Inverts the range.
+func (r *Range) Inside() *Range {
+	r.inside = true
+	return r
+}
+
+// Generates the range's string representation so it can be sent to the
+// monitoring system.
+func (r *Range) String() string {
+	var start, inside string
+
+	switch r.start {
+	case "":
+		start = "~"
+	case "0":
+		start = ""
+	default:
+		start = r.start
+	}
+
+	if r.inside {
+		inside = "@"
+	}
+
+	return inside + start + ":" + r.end
+}

pkg/perfdata/range_test.go

@@ -0,0 +1,67 @@
+package perfdata // import nocternity.net/gomonop/pkg/perfdata
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRangeMaxInvalid(t *testing.T) {
+	assert.Panics(
+		t, func() { RangeMax("") },
+		"Created PerfDataRange with invalid max value",
+	)
+}
+
+func TestRangeMax(t *testing.T) {
+	value := "123"
+	pdr := RangeMax(value)
+	assert.Equal(t, "0", pdr.start, "Min value should be '0'")
+	assert.Equal(t, value, pdr.end, "Max value not copied to PerfDataRange")
+	assert.False(t, pdr.inside, "Inside flag should not be set")
+}
+
+func TestRangeMinMaxInvalid(t *testing.T) {
+	assert.Panics(
+		t, func() { RangeMinMax("", "123") },
+		"Created PerfDataRange with invalid min value",
+	)
+	assert.Panics(
+		t, func() { RangeMinMax("123", "") },
+		"Created PerfDataRange with invalid max value",
+	)
+}
+
+func TestRangeMinMax(t *testing.T) {
+	min, max := "123", "456"
+	pdr := RangeMinMax(min, max)
+	assert.Equal(t, min, pdr.start, "Min value not copied to PerfDataRange")
+	assert.Equal(t, max, pdr.end, "Max value not copied to PerfDataRange")
+	assert.False(t, pdr.inside, "Inside flag should not be set")
+}
+
+func TestRangeInside(t *testing.T) {
+	pdr := &Range{}
+	pdr = pdr.Inside()
+	assert.True(t, pdr.inside, "Inside flag should be set")
+	pdr = pdr.Inside()
+	assert.True(t, pdr.inside, "Inside flag should still be set")
+}
+
+func TestRangeString(t *testing.T) {
+	type Test struct {
+		pdr Range
+		out string
+	}
+	tests := []Test{
+		{pdr: Range{start: "Y", end: "X"}, out: "Y:X"},
+		{pdr: Range{end: "X"}, out: "~:X"},
+		{pdr: Range{start: "0", end: "X"}, out: ":X"},
+		{pdr: Range{inside: true, start: "Y", end: "X"}, out: "@Y:X"},
+	}
+
+	for _, test := range tests {
+		result := test.pdr.String()
+		assert.Equal(t, test.out, result, "Expected '%s', got '%s'", test.out, result)
+	}
+}

pkg/perfdata/units.go

@@ -0,0 +1,20 @@
+package perfdata // import nocternity.net/gomonop/pkg/perfdata
+
+// Units of measurement, which may be used to qualify the performance data.
+type UnitOfMeasurement int
+
+const (
+	UomNone UnitOfMeasurement = iota
+	UomSeconds
+	UomPercent
+	UomBytes
+	UomKilobytes
+	UomMegabytes
+	UomGigabytes
+	UomTerabytes
+	UomCounter
+)
+
+func (u UnitOfMeasurement) String() string {
+	return [...]string{"", "s", "%", "B", "KB", "MB", "GB", "TB", "c"}[u]
+}

pkg/perfdata/units_test.go

@@ -0,0 +1,26 @@
+package perfdata // import nocternity.net/gomonop/pkg/perfdata
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestUnitsToString(t *testing.T) {
+	checks := map[UnitOfMeasurement]string{
+		UomNone:      "",
+		UomSeconds:   "s",
+		UomPercent:   "%",
+		UomBytes:     "B",
+		UomKilobytes: "KB",
+		UomMegabytes: "MB",
+		UomGigabytes: "GB",
+		UomTerabytes: "TB",
+		UomCounter:   "c",
+	}
+
+	for u, s := range checks {
+		result := u.String()
+		assert.Equal(t, s, result, "Expected '%s', got '%s'", s, result)
+	}
+}

pkg/plugin/plugin.go

@@ -1,122 +1,20 @@
-// Package plugin implements a helper that can be used to implement a Nagios,
-// Centreon, Icinga... service monitoring plugin.
-package plugin // import nocternity.net/gomonop/pkg/perfdata
+package plugin // import nocternity.net/gomonop/pkg/plugin
 
-import (
-	"container/list"
-	"fmt"
-	"os"
-	"strings"
+import "nocternity.net/gomonop/pkg/results"
 
-	"nocternity.net/gomonop/pkg/perfdata"
-)
+// Plugin represents the interface to a monitoring plugin.
+type Plugin interface {
+	// Results accesses the results of the monitoring plugin.
+	Results() *results.Results
 
-// Status represents the return status of the monitoring plugin. The
-// corresponding integer value will be used as the program's exit code,
-// to be interpreted by the monitoring system.
-type Status int
+	// CheckArguments ensures that the arguments that were passed to the plugin
+	// actually make sense. Errors should be stored in the plugin's results.
+	CheckArguments() bool
 
-// Plugin exit statuses.
-const (
-	OK Status = iota
-	WARNING
-	CRITICAL
-	UNKNOWN
-)
-
-// String representations of the plugin statuses.
-func (s Status) String() string {
-	return [...]string{"OK", "WARNING", "ERROR", "UNKNOWN"}[s]
+	// RunCheck actually runs whatever checks are implemented by the plugin and
+	// updates the results accordingly.
+	RunCheck()
 }
 
-// Plugin represents the monitoring plugin's state, including its name,
-// return status and message, additional lines of text, and performance
-// data to be encoded in the output.
-type Plugin struct {
-	name      string
-	status    Status
-	message   string
-	extraText *list.List
-	perfData  map[string]*perfdata.PerfData
-}
-
-// New creates the plugin with `name` as its name and an unknown status.
-func New(name string) *Plugin {
-	p := new(Plugin)
-	p.name = name
-	p.status = UNKNOWN
-	p.message = "no status set"
-	p.perfData = make(map[string]*perfdata.PerfData)
-	return p
-}
-
-// SetState sets the plugin's output code to `status` and its message to
-// the specified `message`.
-func (p *Plugin) SetState(status Status, message string) {
-	p.status = status
-	p.message = message
-}
-
-// AddLine adds the specified string to the extra output text buffer.
-func (p *Plugin) AddLine(line string) {
-	if p.extraText == nil {
-		p.extraText = list.New()
-	}
-	p.extraText.PushBack(line)
-}
-
-// AddLinef formats the input and adds it to the text buffer.
-func (p *Plugin) AddLinef(format string, data ...interface{}) {
-	p.AddLine(fmt.Sprintf(format, data...))
-}
-
-// AddLines add the specified `lines` to the output text.
-func (p *Plugin) AddLines(lines []string) {
-	for _, line := range lines {
-		p.AddLine(line)
-	}
-}
-
-// AddPerfData adds performance data described by the "pd" argument to the
-// output's performance data. If two performance data records are added for
-// the same label, the program panics.
-func (p *Plugin) AddPerfData(pd *perfdata.PerfData) {
-	_, exists := p.perfData[pd.Label]
-	if exists {
-		panic("duplicate performance data " + pd.Label)
-	}
-	p.perfData[pd.Label] = pd
-}
-
-// Done generates the plugin's text output from its name, status, text data
-// and performance data, before exiting with the code corresponding to the
-// status.
-func (p *Plugin) Done() {
-	var strBuilder strings.Builder
-	strBuilder.WriteString(p.name)
-	strBuilder.WriteString(" ")
-	strBuilder.WriteString(p.status.String())
-	strBuilder.WriteString(": ")
-	strBuilder.WriteString(p.message)
-	if len(p.perfData) > 0 {
-		strBuilder.WriteString(" | ")
-		needSep := false
-		for _, data := range p.perfData {
-			if needSep {
-				strBuilder.WriteString(", ")
-			} else {
-				needSep = true
-			}
-			strBuilder.WriteString(data.String())
-		}
-	}
-	if p.extraText != nil {
-		for em := p.extraText.Front(); em != nil; em = em.Next() {
-			strBuilder.WriteString("\n")
-			//nolint:forcetypeassert // we want to panic if this isn't a string
-			strBuilder.WriteString(em.Value.(string))
-		}
-	}
-	fmt.Println(strBuilder.String())
-	os.Exit(int(p.status))
-}
+// Builder is a function that can be called in order to instantiate a plugin.
+type Builder func() Plugin

pkg/program/program.go

@@ -1,9 +0,0 @@
-package program // import nocternity.net/gomonop/pkg/program
-
-type Program interface {
-	CheckArguments() bool
-	RunCheck()
-	Done()
-}
-
-type Builder func() Program

pkg/results/results.go

@@ -0,0 +1,107 @@
+// Package results implements a helper that can be used to store the results of
+// a Nagios, Centreon, Icinga... service monitoring plugin, and convert them to
+// text which can be sent to the monitoring server.
+package results // import nocternity.net/gomonop/pkg/results
+
+import (
+	"container/list"
+	"fmt"
+	"strings"
+
+	"nocternity.net/gomonop/pkg/perfdata"
+)
+
+// Results represents the monitoring plugin's results, including its name,
+// return status and message, additional lines of text, and performance
+// data to be encoded in the output.
+type Results struct {
+	name      string
+	status    Status
+	message   string
+	extraText *list.List
+	perfData  map[string]*perfdata.PerfData
+}
+
+// New creates the plugin with `name` as its name and an unknown status.
+func New(name string) *Results {
+	p := new(Results)
+	p.name = name
+	p.status = StatusUnknown
+	p.message = "no status set"
+	p.perfData = make(map[string]*perfdata.PerfData)
+	return p
+}
+
+// SetState sets the plugin's output code to `status` and its message to
+// the specified `message`.
+func (p *Results) SetState(status Status, message string) {
+	p.status = status
+	p.message = message
+}
+
+// AddLine adds the specified string to the extra output text buffer.
+func (p *Results) AddLine(line string) {
+	if p.extraText == nil {
+		p.extraText = list.New()
+	}
+	p.extraText.PushBack(line)
+}
+
+// AddLinef formats the input and adds it to the text buffer.
+func (p *Results) AddLinef(format string, data ...interface{}) {
+	p.AddLine(fmt.Sprintf(format, data...))
+}
+
+// AddLines add the specified `lines` to the output text.
+func (p *Results) AddLines(lines []string) {
+	for _, line := range lines {
+		p.AddLine(line)
+	}
+}
+
+// AddPerfData adds performance data described by the "pd" argument to the
+// output's performance data. If two performance data records are added for
+// the same label, the program panics.
+func (p *Results) AddPerfData(pd *perfdata.PerfData) {
+	_, exists := p.perfData[pd.Label]
+	if exists {
+		panic("duplicate performance data " + pd.Label)
+	}
+	p.perfData[pd.Label] = pd
+}
+
+// String generates the plugin's text output from its name, status, text data
+// and performance data.
+func (p *Results) String() string {
+	var strBuilder strings.Builder
+	strBuilder.WriteString(p.name)
+	strBuilder.WriteString(" ")
+	strBuilder.WriteString(p.status.String())
+	strBuilder.WriteString(": ")
+	strBuilder.WriteString(p.message)
+	if len(p.perfData) > 0 {
+		strBuilder.WriteString(" | ")
+		needSep := false
+		for _, data := range p.perfData {
+			if needSep {
+				strBuilder.WriteString(", ")
+			} else {
+				needSep = true
+			}
+			strBuilder.WriteString(data.String())
+		}
+	}
+	if p.extraText != nil {
+		for em := p.extraText.Front(); em != nil; em = em.Next() {
+			strBuilder.WriteString("\n")
+			//nolint:forcetypeassert // we want to panic if this isn't a string
+			strBuilder.WriteString(em.Value.(string))
+		}
+	}
+	return strBuilder.String()
+}
+
+// ExitCode returns the plugin's exit code.
+func (p *Results) ExitCode() int {
+	return int(p.status)
+}

pkg/results/results_test.go

@@ -0,0 +1,175 @@
+package results // import nocternity.net/gomonop/pkg/results
+
+import (
+	"container/list"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"nocternity.net/gomonop/pkg/perfdata"
+)
+
+func TestNew(t *testing.T) {
+	p := New("test")
+
+	assert.Equal(t, p.name, "test")
+	assert.Equal(t, p.status, StatusUnknown)
+	assert.Equal(t, p.message, "no status set")
+	assert.Nil(t, p.extraText)
+	assert.NotNil(t, p.perfData)
+}
+
+func TestSetState(t *testing.T) {
+	p := Results{}
+
+	p.SetState(StatusWarning, "test")
+
+	assert.Equal(t, p.status, StatusWarning)
+	assert.Equal(t, p.message, "test")
+}
+
+func TestAddLineFirst(t *testing.T) {
+	p := Results{}
+
+	p.AddLine("test")
+
+	assert.NotNil(t, p.extraText)
+	assert.Equal(t, p.extraText.Len(), 1)
+	assert.Equal(t, p.extraText.Front().Value, "test")
+}
+
+func TestAddLineNext(t *testing.T) {
+	p := Results{}
+	p.extraText = list.New()
+
+	p.AddLine("test")
+
+	assert.Equal(t, p.extraText.Len(), 1)
+	assert.Equal(t, p.extraText.Front().Value, "test")
+}
+
+func TestAddLinef(t *testing.T) {
+	p := Results{}
+
+	p.AddLinef("test %d", 123)
+
+	assert.Equal(t, p.extraText.Len(), 1)
+	assert.Equal(t, p.extraText.Front().Value, "test 123")
+}
+
+func TestAddLines(t *testing.T) {
+	p := Results{}
+
+	p.AddLines([]string{"test", "test2"})
+
+	assert.Equal(t, p.extraText.Len(), 2)
+	assert.Equal(t, p.extraText.Front().Value, "test")
+	assert.Equal(t, p.extraText.Front().Next().Value, "test2")
+}
+
+func TestAddPerfData(t *testing.T) {
+	p := Results{}
+	p.perfData = make(map[string]*perfdata.PerfData)
+
+	p.AddPerfData(&perfdata.PerfData{Label: "test"})
+
+	value, ok := p.perfData["test"]
+	assert.True(t, ok)
+	assert.Equal(t, value.Label, "test")
+}
+
+func TestAddPerfDataDuplicate(t *testing.T) {
+	p := Results{}
+	p.perfData = make(map[string]*perfdata.PerfData)
+	p.perfData["test"] = &perfdata.PerfData{Label: "test"}
+
+	assert.Panics(t, func() { p.AddPerfData(&perfdata.PerfData{Label: "test"}) })
+}
+
+func TestString(t *testing.T) {
+	type Test struct {
+		Results
+		expected string
+	}
+
+	pdat := perfdata.PerfData{Label: "test"}
+	tests := []Test{
+		{
+			Results{
+				name:     "test",
+				status:   StatusWarning,
+				message:  "test",
+				perfData: make(map[string]*perfdata.PerfData),
+			},
+			"test WARNING: test",
+		},
+		{
+			func() Results {
+				p := Results{
+					name:      "test",
+					status:    StatusWarning,
+					message:   "test",
+					perfData:  make(map[string]*perfdata.PerfData),
+					extraText: list.New(),
+				}
+				p.extraText.PushBack("test 1")
+				p.extraText.PushBack("test 2")
+				return p
+			}(),
+			"test WARNING: test\ntest 1\ntest 2",
+		},
+		{
+			func() Results {
+				p := Results{
+					name:     "test",
+					status:   StatusWarning,
+					message:  "test",
+					perfData: make(map[string]*perfdata.PerfData),
+				}
+				p.perfData["test 1"] = &pdat
+				p.perfData["test 2"] = &pdat
+				return p
+			}(),
+			"test WARNING: test | " + pdat.String() + ", " +
+				pdat.String(),
+		},
+		{
+			func() Results {
+				p := Results{
+					name:      "test",
+					status:    StatusWarning,
+					message:   "test",
+					perfData:  make(map[string]*perfdata.PerfData),
+					extraText: list.New(),
+				}
+				p.perfData["test 1"] = &pdat
+				p.perfData["test 2"] = &pdat
+				p.extraText.PushBack("test 1")
+				p.extraText.PushBack("test 2")
+				return p
+			}(),
+			"test WARNING: test | " + pdat.String() + ", " +
+				pdat.String() + "\ntest 1\ntest 2",
+		},
+	}
+
+	for _, test := range tests {
+		result := test.Results.String()
+		assert.Equal(t, test.expected, result, "Expected '%s', got '%s'", test.expected, result)
+	}
+}
+
+func TestExitCode(t *testing.T) {
+	p := Results{}
+
+	p.status = StatusOK
+	assert.Equal(t, int(StatusOK), p.ExitCode())
+
+	p.status = StatusWarning
+	assert.Equal(t, int(StatusWarning), p.ExitCode())
+
+	p.status = StatusCritical
+	assert.Equal(t, int(StatusCritical), p.ExitCode())
+
+	p.status = StatusUnknown
+	assert.Equal(t, int(StatusUnknown), p.ExitCode())
+}

pkg/results/status.go

@@ -0,0 +1,19 @@
+package results // import nocternity.net/gomonop/pkg/results
+
+// Status represents the return status of the monitoring plugin. The
+// corresponding integer value will be used as the program's exit code,
+// to be interpreted by the monitoring system.
+type Status int
+
+// Plugin exit statuses.
+const (
+	StatusOK Status = iota
+	StatusWarning
+	StatusCritical
+	StatusUnknown
+)
+
+// String representations of the plugin statuses.
+func (s Status) String() string {
+	return [...]string{"OK", "WARNING", "ERROR", "UNKNOWN"}[s]
+}

pkg/results/status_test.go

@@ -0,0 +1,26 @@
+package results // import nocternity.net/gomonop/pkg/results
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestStatusDefaultOK(t *testing.T) {
+	var s Status
+	assert.Equal(t, StatusOK, s)
+}
+
+func TestStatusToString(t *testing.T) {
+	assert.Equal(t, "OK", StatusOK.String())
+	assert.Equal(t, "WARNING", StatusWarning.String())
+	assert.Equal(t, "ERROR", StatusCritical.String())
+	assert.Equal(t, "UNKNOWN", StatusUnknown.String())
+}
+
+func TestStatusToInt(t *testing.T) {
+	assert.Equal(t, 0, int(StatusOK))
+	assert.Equal(t, 1, int(StatusWarning))
+	assert.Equal(t, 2, int(StatusCritical))
+	assert.Equal(t, 3, int(StatusUnknown))
+}

pkg/version/version_test.go

@@ -0,0 +1,31 @@
+package version // import nocternity.net/gomonop/pkg/version
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestVersion(t *testing.T) {
+	type Test struct {
+		version, commit, status, target, expected string
+	}
+
+	tests := []Test{
+		{"", "COMMIT", "clean", "TARGET", "development version (COMMIT) TARGET"},
+		{"VERSION", "COMMIT", "clean", "TARGET", "VERSION (COMMIT) TARGET"},
+		{"", "COMMIT", "dirty", "TARGET", "development version (COMMIT*) TARGET"},
+		{"VERSION", "COMMIT", "dirty", "TARGET", "VERSION (COMMIT*) TARGET"},
+	}
+
+	for _, test := range tests {
+		version = test.version
+		commit = test.commit
+		status = test.status
+		target = test.target
+
+		result := Version()
+
+		assert.Equal(t, test.expected, result, "Expected '%s', got '%s'", test.expected, result)
+	}
+}