Updated test to verify expected behavior

command/command_test.go

@@ -20,6 +20,13 @@ func fatalCommand(t *testing.T, m Meta) {
 		err.String())
 }
 
+func outputCommand(t *testing.T, m Meta) (string, string) {
+	ui := m.Ui.(*packer.BasicUi)
+	out := ui.Writer.(*bytes.Buffer)
+	err := ui.ErrorWriter.(*bytes.Buffer)
+	return out.String(), err.String()
+}
+
 func testFixture(n string) string {
 	return filepath.Join(fixturesDir, n)
 }

command/test-fixtures/validate/template.json

@@ -6,5 +6,5 @@
       "content":"chocolate"
     }
   ],
-  "min_packer_version":"0.8.0"
+  "min_packer_version":"101.0.0"
 }

command/validate_test.go

@@ -5,28 +5,40 @@ import (
 	"testing"
 )
 
-func TestValidateCommand(t *testing.T) {
+func TestValidateCommandOKVersion(t *testing.T) {
 	c := &ValidateCommand{
 		Meta: testMetaFile(t),
 	}
-
 	args := []string{
 		filepath.Join(testFixture("validate"), "template.json"),
 	}
 
-	defer cleanup()
-
+	// This should pass with a valid configuration version
+	c.CoreConfig.Version = "102.0.0"
 	if code := c.Run(args); code != 0 {
 		fatalCommand(t, c.Meta)
 	}
-
-	if !fileExists("chocolate.txt") {
-		t.Error("Expected to find chocolate.txt")
-	}
-	if !fileExists("vanilla.txt") {
-		t.Error("Expected to find vanilla.txt")
-	}
-	if fileExists("cherry.txt") {
-		t.Error("Expected NOT to find cherry.txt")
-	}
+}
+
+func TestValidateCommandBadVersion(t *testing.T) {
+	c := &ValidateCommand{
+		Meta: testMetaFile(t),
+	}
+	args := []string{
+		filepath.Join(testFixture("validate"), "template.json"),
+	}
+
+	// This should fail with an invalid configuration version
+	c.CoreConfig.Version = "100.0.0"
+	if code := c.Run(args); code != 1 {
+		t.Errorf("Expected exit code 1")
+	}
+
+	stdout, stderr := outputCommand(t, c.Meta)
+	expected := `Error initializing core: This template requires Packer version 101.0.0 or higher; using 100.0.0
+`
+	if stderr != expected {
+		t.Fatalf("Expected:\n%s\nFound:\n%s\n", expected, stderr)
+	}
+	t.Log(stdout)
 }

packer/core.go

@@ -246,8 +246,7 @@ func (c *Core) validate() error {
 
 		if versionActual.LessThan(versionMin) {
 			return fmt.Errorf(
-				"This template requires a minimum Packer version of %s,\n"+
-					"but version %s is running.",
+				"This template requires Packer version %s or higher; using %s",
 				versionMin,
 				versionActual)
 		}