Make sure template inspector always prints a carriage return.

To match with the raw inspector.
Adds tests to verify its functionality.

Signed-off-by: David Calavera <david.calavera@gmail.com>

api/client/inspect/inspector.go

@@ -48,6 +48,10 @@ func (i *TemplateInspector) Inspect(typedElement interface{}, rawElement []byte)
 
 // Flush write the result of inspecting all elements into the output stream.
 func (i *TemplateInspector) Flush() error {
+	if i.buffer.Len() == 0 {
+		_, err := io.WriteString(i.outputStream, "\n")
+		return err
+	}
 	_, err := io.Copy(i.outputStream, i.buffer)
 	return err
 }

api/client/inspect/inspector_test.go

@@ -0,0 +1,189 @@
+package inspect
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+	"text/template"
+)
+
+type testElement struct {
+	DNS string `json:"Dns"`
+}
+
+func TestTemplateInspectorDefault(t *testing.T) {
+	b := new(bytes.Buffer)
+	tmpl, err := template.New("test").Parse("{{.DNS}}")
+	if err != nil {
+		t.Fatal(err)
+	}
+	i := NewTemplateInspector(b, tmpl)
+	if err := i.Inspect(testElement{"0.0.0.0"}, nil); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := i.Flush(); err != nil {
+		t.Fatal(err)
+	}
+	if b.String() != "0.0.0.0\n" {
+		t.Fatalf("Expected `0.0.0.0\\n`, got `%s`", b.String())
+	}
+}
+
+func TestTemplateInspectorEmpty(t *testing.T) {
+	b := new(bytes.Buffer)
+	tmpl, err := template.New("test").Parse("{{.DNS}}")
+	if err != nil {
+		t.Fatal(err)
+	}
+	i := NewTemplateInspector(b, tmpl)
+
+	if err := i.Flush(); err != nil {
+		t.Fatal(err)
+	}
+	if b.String() != "\n" {
+		t.Fatalf("Expected `\\n`, got `%s`", b.String())
+	}
+}
+
+func TestTemplateInspectorTemplateError(t *testing.T) {
+	b := new(bytes.Buffer)
+	tmpl, err := template.New("test").Parse("{{.Foo}}")
+	if err != nil {
+		t.Fatal(err)
+	}
+	i := NewTemplateInspector(b, tmpl)
+
+	err = i.Inspect(testElement{"0.0.0.0"}, nil)
+	if err == nil {
+		t.Fatal("Expected error got nil")
+	}
+
+	if !strings.HasPrefix(err.Error(), "Template parsing error") {
+		t.Fatalf("Expected template error, got %v", err)
+	}
+}
+
+func TestTemplateInspectorRawFallback(t *testing.T) {
+	b := new(bytes.Buffer)
+	tmpl, err := template.New("test").Parse("{{.Dns}}")
+	if err != nil {
+		t.Fatal(err)
+	}
+	i := NewTemplateInspector(b, tmpl)
+	if err := i.Inspect(testElement{"0.0.0.0"}, []byte(`{"Dns": "0.0.0.0"}`)); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := i.Flush(); err != nil {
+		t.Fatal(err)
+	}
+	if b.String() != "0.0.0.0\n" {
+		t.Fatalf("Expected `0.0.0.0\\n`, got `%s`", b.String())
+	}
+}
+
+func TestTemplateInspectorRawFallbackError(t *testing.T) {
+	b := new(bytes.Buffer)
+	tmpl, err := template.New("test").Parse("{{.Dns}}")
+	if err != nil {
+		t.Fatal(err)
+	}
+	i := NewTemplateInspector(b, tmpl)
+	err = i.Inspect(testElement{"0.0.0.0"}, []byte(`{"Foo": "0.0.0.0"}`))
+	if err == nil {
+		t.Fatal("Expected error got nil")
+	}
+
+	if !strings.HasPrefix(err.Error(), "Template parsing error") {
+		t.Fatalf("Expected template error, got %v", err)
+	}
+}
+
+func TestTemplateInspectorMultiple(t *testing.T) {
+	b := new(bytes.Buffer)
+	tmpl, err := template.New("test").Parse("{{.DNS}}")
+	if err != nil {
+		t.Fatal(err)
+	}
+	i := NewTemplateInspector(b, tmpl)
+
+	if err := i.Inspect(testElement{"0.0.0.0"}, nil); err != nil {
+		t.Fatal(err)
+	}
+	if err := i.Inspect(testElement{"1.1.1.1"}, nil); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := i.Flush(); err != nil {
+		t.Fatal(err)
+	}
+	if b.String() != "0.0.0.0\n1.1.1.1\n" {
+		t.Fatalf("Expected `0.0.0.0\\n1.1.1.1\\n`, got `%s`", b.String())
+	}
+}
+
+func TestIndentedInspectorDefault(t *testing.T) {
+	b := new(bytes.Buffer)
+	i := NewIndentedInspector(b)
+	if err := i.Inspect(testElement{"0.0.0.0"}, nil); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := i.Flush(); err != nil {
+		t.Fatal(err)
+	}
+
+	expected := `[
+    {
+        "Dns": "0.0.0.0"
+    }
+]
+`
+	if b.String() != expected {
+		t.Fatalf("Expected `%s`, got `%s`", expected, b.String())
+	}
+}
+
+func TestIndentedInspectorMultiple(t *testing.T) {
+	b := new(bytes.Buffer)
+	i := NewIndentedInspector(b)
+	if err := i.Inspect(testElement{"0.0.0.0"}, nil); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := i.Inspect(testElement{"1.1.1.1"}, nil); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := i.Flush(); err != nil {
+		t.Fatal(err)
+	}
+
+	expected := `[
+    {
+        "Dns": "0.0.0.0"
+    },
+    {
+        "Dns": "1.1.1.1"
+    }
+]
+`
+	if b.String() != expected {
+		t.Fatalf("Expected `%s`, got `%s`", expected, b.String())
+	}
+}
+
+func TestIndentedInspectorEmpty(t *testing.T) {
+	b := new(bytes.Buffer)
+	i := NewIndentedInspector(b)
+
+	if err := i.Flush(); err != nil {
+		t.Fatal(err)
+	}
+
+	expected := "[]\n"
+	if b.String() != expected {
+		t.Fatalf("Expected `%s`, got `%s`", expected, b.String())
+	}
+}