Added 'Description()' to 'sshKeyPair'.

Also cleaned up tests.

builder/virtualbox/common/sshkeypair.go

@@ -90,6 +90,10 @@ type sshKeyPair interface {
 	// Bits returns the bits of entropy.
 	Bits() int
 
+	// Description returns a brief description of the key pair that
+	// is suitable for log messages or printing.
+	Description() string
+
 	// PrivateKeyPemBlock returns a slice of bytes representing
 	// the private key in ASN.1, DER format in a PEM block.
 	PrivateKeyPemBlock() []byte
@@ -123,6 +127,10 @@ func (o defaultSshKeyPair) Bits() int {
 	return o.bits
 }
 
+func (o defaultSshKeyPair) Description() string {
+	return o.kind.String() + " " + strconv.Itoa(o.bits)
+}
+
 func (o defaultSshKeyPair) PrivateKeyPemBlock() []byte {
 	t := "UNKNOWN PRIVATE KEY"
 

builder/virtualbox/common/sshkeypair_test.go

@@ -3,27 +3,67 @@ package common
 import (
 	"crypto/rand"
 	"errors"
+	"strconv"
 	"testing"
 
 	"golang.org/x/crypto/ssh"
 )
 
+// expected contains the data that the key pair should contain.
+type expected struct {
+	kind sshKeyPairType
+	bits int
+	desc string
+}
+
+func (o expected) matches(kp sshKeyPair) error {
+	if o.kind.String() == "" {
+		return errors.New("expected kind's value cannot be empty")
+	}
+
+	if o.bits <= 0 {
+		return errors.New("expected bits' value cannot be less than or equal to 0")
+	}
+
+	if o.desc == "" {
+		return errors.New("expected description's value cannot be empty")
+	}
+
+	if kp.Type() != o.kind {
+		return errors.New("expected key pair type to be " +
+			o.kind.String() + " - got '" + kp.Type().String() + "'")
+	}
+
+	if kp.Bits() != o.bits {
+		return errors.New("expected key pair to be " +
+			strconv.Itoa(o.bits) + " bits - got " + strconv.Itoa(kp.Bits()))
+	}
+
+	expDescription := kp.Type().String() + " " + strconv.Itoa(o.bits)
+	if kp.Description() != expDescription {
+		return errors.New("expected key pair description to be '" +
+			expDescription + "' - got '" + kp.Description() + "'")
+	}
+
+	err := verifySshKeyPair(kp)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
 func TestDefaultSshKeyPairBuilder_Build_Default(t *testing.T) {
 	kp, err := newSshKeyPairBuilder().Build()
 	if err != nil {
 		t.Fatal(err.Error())
 	}
 
-	if kp.Type() != ecdsaSsh {
-		t.Fatal("Expected key pair type to be",
-			ecdsaSsh.String(), "- got", kp.Type())
-	}
-
-	if kp.Bits() != 521 {
-		t.Fatal("Expected key pair to be 521 bits - got", kp.Bits())
-	}
-
-	err = verifySshKeyPair(kp)
+	err = expected{
+		kind: ecdsaSsh,
+		bits: 521,
+		desc: "ecdsa 521",
+	}.matches(kp)
 	if err != nil {
 		t.Fatal(err.Error())
 	}
@@ -35,16 +75,11 @@ func TestDefaultSshKeyPairBuilder_Build_EcdsaDefault(t *testing.T) {
 		t.Fatal(err.Error())
 	}
 
-	if kp.Type() != ecdsaSsh {
-		t.Fatal("Expected key pair type to be",
-			ecdsaSsh.String(), "- got", kp.Type())
-	}
-
-	if kp.Bits() != 521 {
-		t.Fatal("Expected key pair to be 521 bits - got", kp.Bits())
-	}
-
-	err = verifySshKeyPair(kp)
+	err = expected{
+		kind: ecdsaSsh,
+		bits: 521,
+		desc: "ecdsa 521",
+	}.matches(kp)
 	if err != nil {
 		t.Fatal(err.Error())
 	}
@@ -56,16 +91,11 @@ func TestDefaultSshKeyPairBuilder_Build_RsaDefault(t *testing.T) {
 		t.Fatal(err.Error())
 	}
 
-	if kp.Type() != rsaSsh {
-		t.Fatal("Expected default key pair type to be",
-			rsaSsh.String(), "- got", kp.Type())
-	}
-
-	if kp.Bits() != 4096 {
-		t.Fatal("Expected key pair to be", 4096, "bits - got", kp.Bits())
-	}
-
-	err = verifySshKeyPair(kp)
+	err = expected{
+		kind: rsaSsh,
+		bits: 4096,
+		desc: "rsa 4096",
+	}.matches(kp)
 	if err != nil {
 		t.Fatal(err.Error())
 	}