test base use cases for feature definition parser

gherkin/parse_feature_test.go

@@ -13,9 +13,27 @@ var testFeatureSamples = map[string]string{
   as gherkin lexer
   I need to be able to parse a feature`,
 	"only_title": `Feature: gherkin`,
+	"empty":      ``,
+	"invalid":    `some text`,
+	"starts_with_newlines": `
+
+  Feature: gherkin`,
 }
 
-func Test_normal_feature_parsing(t *testing.T) {
+func (a *AST) assertMatchesTypes(expected []lexer.TokenType, t *testing.T) {
+	key := -1
+	for item := a.head; item != nil; item = item.next {
+		key += 1
+		if expected[key] != item.value.Type {
+			t.Fatalf("expected ast token '%s', but got '%s' at position: %d", expected[key], item.value.Type, key)
+		}
+	}
+	if len(expected)-1 != key {
+		t.Fatalf("expected ast length %d, does not match actual: %d", len(expected), key+1)
+	}
+}
+
+func Test_parse_normal_feature(t *testing.T) {
 	p := &parser{
 		lx:   lexer.New(strings.NewReader(testFeatureSamples["full"])),
 		path: "some.feature",
@@ -28,4 +46,93 @@ func Test_normal_feature_parsing(t *testing.T) {
 	if ft.Title != "gherkin parser" {
 		t.Fatalf("the feature title '%s' was not expected", ft.Title)
 	}
+	if len(ft.Description) == 0 {
+		t.Fatalf("expected a feature description to be available")
+	}
+
+	ft.AST.assertMatchesTypes([]lexer.TokenType{
+		lexer.FEATURE,
+		lexer.TEXT,
+		lexer.TEXT,
+		lexer.TEXT,
+		lexer.EOF,
+	}, t)
+}
+
+func Test_parse_feature_without_description(t *testing.T) {
+	p := &parser{
+		lx:   lexer.New(strings.NewReader(testFeatureSamples["only_title"])),
+		path: "some.feature",
+		ast:  newAST(),
+	}
+	ft, err := p.parseFeature()
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	if ft.Title != "gherkin" {
+		t.Fatalf("the feature title '%s' was not expected", ft.Title)
+	}
+	if len(ft.Description) > 0 {
+		t.Fatalf("feature description was not expected")
+	}
+
+	ft.AST.assertMatchesTypes([]lexer.TokenType{
+		lexer.FEATURE,
+		lexer.EOF,
+	}, t)
+}
+
+func Test_parse_empty_feature_file(t *testing.T) {
+	p := &parser{
+		lx:   lexer.New(strings.NewReader(testFeatureSamples["empty"])),
+		path: "some.feature",
+		ast:  newAST(),
+	}
+	_, err := p.parseFeature()
+	if err != ErrEmpty {
+		t.Fatalf("expected an empty file error, but got none")
+	}
+	p.ast.assertMatchesTypes([]lexer.TokenType{
+		lexer.EOF,
+	}, t)
+}
+
+func Test_parse_invalid_feature_with_random_text(t *testing.T) {
+	p := &parser{
+		lx:   lexer.New(strings.NewReader(testFeatureSamples["invalid"])),
+		path: "some.feature",
+		ast:  newAST(),
+	}
+	_, err := p.parseFeature()
+	if err == nil {
+		t.Fatalf("expected an error but got none")
+	}
+	p.ast.assertMatchesTypes([]lexer.TokenType{
+		lexer.TEXT,
+	}, t)
+}
+
+func Test_parse_feature_with_newlines(t *testing.T) {
+	p := &parser{
+		lx:   lexer.New(strings.NewReader(testFeatureSamples["starts_with_newlines"])),
+		path: "some.feature",
+		ast:  newAST(),
+	}
+	ft, err := p.parseFeature()
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	if ft.Title != "gherkin" {
+		t.Fatalf("the feature title '%s' was not expected", ft.Title)
+	}
+	if len(ft.Description) > 0 {
+		t.Fatalf("feature description was not expected")
+	}
+
+	ft.AST.assertMatchesTypes([]lexer.TokenType{
+		lexer.NEW_LINE,
+		lexer.NEW_LINE,
+		lexer.FEATURE,
+		lexer.EOF,
+	}, t)
 }