Add delete operation

codecov.yml

@@ -3,7 +3,7 @@ coverage:
     project:
       default:
         target: 75%
-        threshold: 5%
+        threshold: 4%
     patch:
       default:
         target: 50%

internal/mongo/errors.go

@@ -0,0 +1,20 @@
+package mongo
+
+// GenerationError is an error from generating MongoDB repository
+type GenerationError string
+
+func (err GenerationError) Error() string {
+	switch err {
+	case OperationNotSupportedError:
+		return "operation not supported"
+	case BsonTagNotFoundError:
+		return "bson tag not found"
+	}
+	return string(err)
+}
+
+// generation error constants
+const (
+	OperationNotSupportedError GenerationError = "ERROR_OPERATION_NOT_SUPPORTED"
+	BsonTagNotFoundError       GenerationError = "ERROR_BSON_TAG_NOT_FOUND"
+)

internal/mongo/generator.go

@@ -2,7 +2,6 @@ package mongo
 
 import (
 	"bytes"
-	"errors"
 	"fmt"
 	"io"
 	"text/template"
@@ -80,35 +79,24 @@ func (g RepositoryGenerator) generateMethodImplementation(methodSpec spec.Method
 	switch operation := methodSpec.Operation.(type) {
 	case spec.FindOperation:
 		return g.generateFindImplementation(operation)
+	case spec.DeleteOperation:
+		return g.generateDeleteImplementation(operation)
 	}
 
-	return "", errors.New("method spec not supported")
+	return "", OperationNotSupportedError
 }
 
 func (g RepositoryGenerator) generateFindImplementation(operation spec.FindOperation) (string, error) {
 	buffer := new(bytes.Buffer)
 
-	var predicates []predicate
+	querySpec, err := g.mongoQuerySpec(operation.Query)
-	for _, predicateSpec := range operation.Query.Predicates {
+	if err != nil {
-		structField, ok := g.StructModel.Fields.ByName(predicateSpec.Field)
+		return "", err
-		if !ok {
-			return "", fmt.Errorf("struct field %s not found", predicateSpec.Field)
-		}
-
-		bsonTag, ok := structField.Tags["bson"]
-		if !ok {
-			return "", fmt.Errorf("struct field %s does not have bson tag", predicateSpec.Field)
-		}
-
-		predicates = append(predicates, predicate{Field: bsonTag[0], Comparator: predicateSpec.Comparator})
 	}
 
 	tmplData := mongoFindTemplateData{
 		EntityType: g.StructModel.Name,
-		QuerySpec: querySpec{
+		QuerySpec:  querySpec,
-			Operator:   operation.Query.Operator,
-			Predicates: predicates,
-		},
 	}
 
 	if operation.Mode == spec.QueryModeOne {
@@ -134,6 +122,64 @@ func (g RepositoryGenerator) generateFindImplementation(operation spec.FindOpera
 	return buffer.String(), nil
 }
 
+func (g RepositoryGenerator) generateDeleteImplementation(operation spec.DeleteOperation) (string, error) {
+	buffer := new(bytes.Buffer)
+
+	querySpec, err := g.mongoQuerySpec(operation.Query)
+	if err != nil {
+		return "", err
+	}
+
+	tmplData := mongoDeleteTemplateData{
+		QuerySpec: querySpec,
+	}
+
+	if operation.Mode == spec.QueryModeOne {
+		tmpl, err := template.New("mongo_repository_deleteone").Parse(deleteOneTemplate)
+		if err != nil {
+			return "", err
+		}
+
+		if err := tmpl.Execute(buffer, tmplData); err != nil {
+			return "", err
+		}
+	} else {
+		tmpl, err := template.New("mongo_repository_deletemany").Parse(deleteManyTemplate)
+		if err != nil {
+			return "", err
+		}
+
+		if err := tmpl.Execute(buffer, tmplData); err != nil {
+			return "", err
+		}
+	}
+
+	return buffer.String(), nil
+}
+
+func (g RepositoryGenerator) mongoQuerySpec(query spec.QuerySpec) (querySpec, error) {
+	var predicates []predicate
+
+	for _, predicateSpec := range query.Predicates {
+		structField, ok := g.StructModel.Fields.ByName(predicateSpec.Field)
+		if !ok {
+			return querySpec{}, fmt.Errorf("struct field %s not found", predicateSpec.Field)
+		}
+
+		bsonTag, ok := structField.Tags["bson"]
+		if !ok {
+			return querySpec{}, BsonTagNotFoundError
+		}
+
+		predicates = append(predicates, predicate{Field: bsonTag[0], Comparator: predicateSpec.Comparator})
+	}
+
+	return querySpec{
+		Operator:   query.Operator,
+		Predicates: predicates,
+	}, nil
+}
+
 func (g RepositoryGenerator) structName() string {
 	return g.InterfaceName + "Mongo"
 }

internal/mongo/generator_test.go

@@ -10,6 +10,36 @@ import (
 	"github.com/sunboyy/repogen/internal/testutils"
 )
 
+var userModel = code.Struct{
+	Name: "UserModel",
+	Fields: code.StructFields{
+		{
+			Name: "ID",
+			Type: code.ExternalType{PackageAlias: "primitive", Name: "ObjectID"},
+			Tags: map[string][]string{"bson": {"_id", "omitempty"}},
+		},
+		{
+			Name: "Username",
+			Type: code.SimpleType("string"),
+			Tags: map[string][]string{"bson": {"username"}},
+		},
+		{
+			Name: "Gender",
+			Type: code.SimpleType("Gender"),
+			Tags: map[string][]string{"bson": {"gender"}},
+		},
+		{
+			Name: "Age",
+			Type: code.SimpleType("int"),
+			Tags: map[string][]string{"bson": {"age"}},
+		},
+		{
+			Name: "AccessToken",
+			Type: code.SimpleType("string"),
+		},
+	},
+}
+
 const expectedConstructorResult = `
 import (
 	"context"
@@ -31,31 +61,6 @@ type UserRepositoryMongo struct {
 `
 
 func TestGenerateConstructor(t *testing.T) {
-	userModel := code.Struct{
-		Name: "UserModel",
-		Fields: code.StructFields{
-			{
-				Name: "ID",
-				Type: code.ExternalType{PackageAlias: "primitive", Name: "ObjectID"},
-				Tags: map[string][]string{"bson": {"_id", "omitempty"}},
-			},
-			{
-				Name: "Username",
-				Type: code.SimpleType("string"),
-				Tags: map[string][]string{"bson": {"username"}},
-			},
-			{
-				Name: "Gender",
-				Type: code.SimpleType("Gender"),
-				Tags: map[string][]string{"bson": {"gender"}},
-			},
-			{
-				Name: "Age",
-				Type: code.SimpleType("int"),
-				Tags: map[string][]string{"bson": {"age"}},
-			},
-		},
-	}
 	generator := mongo.NewGenerator(userModel, "UserRepository")
 	buffer := new(bytes.Buffer)
 
@@ -75,7 +80,7 @@ type GenerateMethodTestCase struct {
 	ExpectedCode string
 }
 
-func TestGenerateMethod(t *testing.T) {
+func TestGenerateMethod_Find(t *testing.T) {
 	testTable := []GenerateMethodTestCase{
 		{
 			Name: "simple find one method",
@@ -489,33 +494,9 @@ func (r *UserRepositoryMongo) FindByGenderIn(ctx context.Context, arg0 []Gender)
 `,
 		},
 	}
+
 	for _, testCase := range testTable {
 		t.Run(testCase.Name, func(t *testing.T) {
-			userModel := code.Struct{
-				Name: "UserModel",
-				Fields: code.StructFields{
-					{
-						Name: "ID",
-						Type: code.ExternalType{PackageAlias: "primitive", Name: "ObjectID"},
-						Tags: map[string][]string{"bson": {"_id", "omitempty"}},
-					},
-					{
-						Name: "Username",
-						Type: code.SimpleType("string"),
-						Tags: map[string][]string{"bson": {"username"}},
-					},
-					{
-						Name: "Gender",
-						Type: code.SimpleType("Gender"),
-						Tags: map[string][]string{"bson": {"gender"}},
-					},
-					{
-						Name: "Age",
-						Type: code.SimpleType("int"),
-						Tags: map[string][]string{"bson": {"age"}},
-					},
-				},
-			}
 			generator := mongo.NewGenerator(userModel, "UserRepository")
 			buffer := new(bytes.Buffer)
 
@@ -530,3 +511,458 @@ func (r *UserRepositoryMongo) FindByGenderIn(ctx context.Context, arg0 []Gender)
 		})
 	}
 }
+
+func TestGenerateMethod_Delete(t *testing.T) {
+	testTable := []GenerateMethodTestCase{
+		{
+			Name: "simple delete one method",
+			MethodSpec: spec.MethodSpec{
+				Name: "DeleteByID",
+				Params: []code.Param{
+					{Name: "ctx", Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Name: "id", Type: code.ExternalType{PackageAlias: "primitive", Name: "ObjectID"}},
+				},
+				Returns: []code.Type{code.SimpleType("bool"), code.SimpleType("error")},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeOne,
+					Query: spec.QuerySpec{
+						Predicates: []spec.Predicate{
+							{Comparator: spec.ComparatorEqual, Field: "ID"},
+						},
+					},
+				},
+			},
+			ExpectedCode: `
+func (r *UserRepositoryMongo) DeleteByID(ctx context.Context, arg0 primitive.ObjectID) (bool, error) {
+	result, err := r.collection.DeleteOne(ctx, bson.M{
+		"_id": arg0,
+	})
+	if err != nil {
+		return false, err
+	}
+	return result.DeletedCount > 0, nil
+}
+`,
+		},
+		{
+			Name: "simple delete many method",
+			MethodSpec: spec.MethodSpec{
+				Name: "DeleteByGender",
+				Params: []code.Param{
+					{Name: "ctx", Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Name: "gender", Type: code.SimpleType("Gender")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{
+						Predicates: []spec.Predicate{
+							{Comparator: spec.ComparatorEqual, Field: "Gender"},
+						},
+					},
+				},
+			},
+			ExpectedCode: `
+func (r *UserRepositoryMongo) DeleteByGender(ctx context.Context, arg0 Gender) (int, error) {
+	result, err := r.collection.DeleteMany(ctx, bson.M{
+		"gender": arg0,
+	})
+	if err != nil {
+		return 0, err
+	}
+	return int(result.DeletedCount), nil
+}
+`,
+		},
+		{
+			Name: "delete with And operator",
+			MethodSpec: spec.MethodSpec{
+				Name: "DeleteByGenderAndAge",
+				Params: []code.Param{
+					{Name: "ctx", Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Name: "gender", Type: code.SimpleType("Gender")},
+					{Name: "age", Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{
+						Operator: spec.OperatorAnd,
+						Predicates: []spec.Predicate{
+							{Comparator: spec.ComparatorEqual, Field: "Gender"},
+							{Comparator: spec.ComparatorEqual, Field: "Age"},
+						},
+					},
+				},
+			},
+			ExpectedCode: `
+func (r *UserRepositoryMongo) DeleteByGenderAndAge(ctx context.Context, arg0 Gender, arg1 int) (int, error) {
+	result, err := r.collection.DeleteMany(ctx, bson.M{
+		"gender": arg0,
+		"age": arg1,
+	})
+	if err != nil {
+		return 0, err
+	}
+	return int(result.DeletedCount), nil
+}
+`,
+		},
+		{
+			Name: "delete with Or operator",
+			MethodSpec: spec.MethodSpec{
+				Name: "DeleteByGenderOrAge",
+				Params: []code.Param{
+					{Name: "ctx", Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Name: "gender", Type: code.SimpleType("Gender")},
+					{Name: "age", Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{
+						Operator: spec.OperatorOr,
+						Predicates: []spec.Predicate{
+							{Comparator: spec.ComparatorEqual, Field: "Gender"},
+							{Comparator: spec.ComparatorEqual, Field: "Age"},
+						},
+					},
+				},
+			},
+			ExpectedCode: `
+func (r *UserRepositoryMongo) DeleteByGenderOrAge(ctx context.Context, arg0 Gender, arg1 int) (int, error) {
+	result, err := r.collection.DeleteMany(ctx, bson.M{
+		"$or": []bson.M{
+			{"gender": arg0},
+			{"age": arg1},
+		},
+	})
+	if err != nil {
+		return 0, err
+	}
+	return int(result.DeletedCount), nil
+}
+`,
+		},
+		{
+			Name: "delete with Not comparator",
+			MethodSpec: spec.MethodSpec{
+				Name: "DeleteByGenderNot",
+				Params: []code.Param{
+					{Name: "ctx", Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Name: "gender", Type: code.SimpleType("Gender")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{
+						Predicates: []spec.Predicate{
+							{Comparator: spec.ComparatorNot, Field: "Gender"},
+						},
+					},
+				},
+			},
+			ExpectedCode: `
+func (r *UserRepositoryMongo) DeleteByGenderNot(ctx context.Context, arg0 Gender) (int, error) {
+	result, err := r.collection.DeleteMany(ctx, bson.M{
+		"gender": bson.M{"$ne": arg0},
+	})
+	if err != nil {
+		return 0, err
+	}
+	return int(result.DeletedCount), nil
+}
+`,
+		},
+		{
+			Name: "delete with LessThan comparator",
+			MethodSpec: spec.MethodSpec{
+				Name: "DeleteByAgeLessThan",
+				Params: []code.Param{
+					{Name: "ctx", Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Name: "age", Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{
+						Predicates: []spec.Predicate{
+							{Comparator: spec.ComparatorLessThan, Field: "Age"},
+						},
+					},
+				},
+			},
+			ExpectedCode: `
+func (r *UserRepositoryMongo) DeleteByAgeLessThan(ctx context.Context, arg0 int) (int, error) {
+	result, err := r.collection.DeleteMany(ctx, bson.M{
+		"age": bson.M{"$lt": arg0},
+	})
+	if err != nil {
+		return 0, err
+	}
+	return int(result.DeletedCount), nil
+}
+`,
+		},
+		{
+			Name: "delete with LessThanEqual comparator",
+			MethodSpec: spec.MethodSpec{
+				Name: "DeleteByAgeLessThanEqual",
+				Params: []code.Param{
+					{Name: "ctx", Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Name: "age", Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{
+						Predicates: []spec.Predicate{
+							{Comparator: spec.ComparatorLessThanEqual, Field: "Age"},
+						},
+					},
+				},
+			},
+			ExpectedCode: `
+func (r *UserRepositoryMongo) DeleteByAgeLessThanEqual(ctx context.Context, arg0 int) (int, error) {
+	result, err := r.collection.DeleteMany(ctx, bson.M{
+		"age": bson.M{"$lte": arg0},
+	})
+	if err != nil {
+		return 0, err
+	}
+	return int(result.DeletedCount), nil
+}
+`,
+		},
+		{
+			Name: "delete with GreaterThan comparator",
+			MethodSpec: spec.MethodSpec{
+				Name: "DeleteByAgeGreaterThan",
+				Params: []code.Param{
+					{Name: "ctx", Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Name: "age", Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{
+						Predicates: []spec.Predicate{
+							{Comparator: spec.ComparatorGreaterThan, Field: "Age"},
+						},
+					},
+				},
+			},
+			ExpectedCode: `
+func (r *UserRepositoryMongo) DeleteByAgeGreaterThan(ctx context.Context, arg0 int) (int, error) {
+	result, err := r.collection.DeleteMany(ctx, bson.M{
+		"age": bson.M{"$gt": arg0},
+	})
+	if err != nil {
+		return 0, err
+	}
+	return int(result.DeletedCount), nil
+}
+`,
+		},
+		{
+			Name: "delete with GreaterThanEqual comparator",
+			MethodSpec: spec.MethodSpec{
+				Name: "DeleteByAgeGreaterThanEqual",
+				Params: []code.Param{
+					{Name: "ctx", Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Name: "age", Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{
+						Predicates: []spec.Predicate{
+							{Comparator: spec.ComparatorGreaterThanEqual, Field: "Age"},
+						},
+					},
+				},
+			},
+			ExpectedCode: `
+func (r *UserRepositoryMongo) DeleteByAgeGreaterThanEqual(ctx context.Context, arg0 int) (int, error) {
+	result, err := r.collection.DeleteMany(ctx, bson.M{
+		"age": bson.M{"$gte": arg0},
+	})
+	if err != nil {
+		return 0, err
+	}
+	return int(result.DeletedCount), nil
+}
+`,
+		},
+		{
+			Name: "delete with Between comparator",
+			MethodSpec: spec.MethodSpec{
+				Name: "DeleteByAgeBetween",
+				Params: []code.Param{
+					{Name: "ctx", Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Name: "fromAge", Type: code.SimpleType("int")},
+					{Name: "toAge", Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{
+						Predicates: []spec.Predicate{
+							{Comparator: spec.ComparatorBetween, Field: "Age"},
+						},
+					},
+				},
+			},
+			ExpectedCode: `
+func (r *UserRepositoryMongo) DeleteByAgeBetween(ctx context.Context, arg0 int, arg1 int) (int, error) {
+	result, err := r.collection.DeleteMany(ctx, bson.M{
+		"age": bson.M{"$gte": arg0, "$lte": arg1},
+	})
+	if err != nil {
+		return 0, err
+	}
+	return int(result.DeletedCount), nil
+}
+`,
+		},
+		{
+			Name: "delete with In comparator",
+			MethodSpec: spec.MethodSpec{
+				Name: "DeleteByGenderIn",
+				Params: []code.Param{
+					{Name: "ctx", Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Name: "gender", Type: code.ArrayType{ContainedType: code.SimpleType("Gender")}},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{
+						Predicates: []spec.Predicate{
+							{Comparator: spec.ComparatorIn, Field: "Gender"},
+						},
+					},
+				},
+			},
+			ExpectedCode: `
+func (r *UserRepositoryMongo) DeleteByGenderIn(ctx context.Context, arg0 []Gender) (int, error) {
+	result, err := r.collection.DeleteMany(ctx, bson.M{
+		"gender": bson.M{"$in": arg0},
+	})
+	if err != nil {
+		return 0, err
+	}
+	return int(result.DeletedCount), nil
+}
+`,
+		},
+	}
+
+	for _, testCase := range testTable {
+		t.Run(testCase.Name, func(t *testing.T) {
+			generator := mongo.NewGenerator(userModel, "UserRepository")
+			buffer := new(bytes.Buffer)
+
+			err := generator.GenerateMethod(testCase.MethodSpec, buffer)
+
+			if err != nil {
+				t.Error(err)
+			}
+			if err := testutils.ExpectMultiLineString(testCase.ExpectedCode, buffer.String()); err != nil {
+				t.Error(err)
+			}
+		})
+	}
+}
+
+type GenerateMethodInvalidTestCase struct {
+	Name          string
+	Method        spec.MethodSpec
+	ExpectedError error
+}
+
+func TestGenerateMethod_Invalid(t *testing.T) {
+	testTable := []GenerateMethodInvalidTestCase{
+		{
+			Name: "operation not supported",
+			Method: spec.MethodSpec{
+				Name: "SearchByID",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.ExternalType{PackageAlias: "primitive", Name: "ObjectID"}},
+				},
+				Returns: []code.Type{
+					code.ArrayType{ContainedType: code.PointerType{ContainedType: code.SimpleType("UserModel")}},
+					code.SimpleType("error"),
+				},
+				Operation: "search",
+			},
+			ExpectedError: mongo.OperationNotSupportedError,
+		},
+		{
+			Name: "bson tag not found",
+			Method: spec.MethodSpec{
+				Name: "FindByAccessToken",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("string")},
+				},
+				Returns: []code.Type{
+					code.ArrayType{ContainedType: code.PointerType{ContainedType: code.SimpleType("UserModel")}},
+					code.SimpleType("error"),
+				},
+				Operation: spec.FindOperation{
+					Mode: spec.QueryModeOne,
+					Query: spec.QuerySpec{
+						Predicates: []spec.Predicate{
+							{Field: "AccessToken", Comparator: spec.ComparatorEqual},
+						},
+					},
+				},
+			},
+			ExpectedError: mongo.BsonTagNotFoundError,
+		},
+	}
+
+	for _, testCase := range testTable {
+		t.Run(testCase.Name, func(t *testing.T) {
+			generator := mongo.NewGenerator(userModel, "UserRepository")
+			buffer := new(bytes.Buffer)
+
+			err := generator.GenerateMethod(testCase.Method, buffer)
+
+			if err != testCase.ExpectedError {
+				t.Errorf("\nExpected = %v\nReceived = %v", testCase.ExpectedError, err)
+			}
+		})
+	}
+}

internal/mongo/templates.go

@@ -70,19 +70,19 @@ func (data mongoMethodTemplateData) Returns() string {
 	return fmt.Sprintf(" (%s)", strings.Join(returns, ", "))
 }
 
-const findOneTemplate = `	var entity {{.EntityType}}
-	if err := r.collection.FindOne(ctx, bson.M{
-{{range $index, $field := .QuerySpec.Predicates}}		{{$field.Code $index}},
-{{end}}	}).Decode(&entity); err != nil {
-		return nil, err
-	}
-	return &entity, nil`
-
 type mongoFindTemplateData struct {
 	EntityType string
 	QuerySpec  querySpec
 }
 
+const findOneTemplate = `	var entity {{.EntityType}}
+	if err := r.collection.FindOne(ctx, bson.M{
+{{.QuerySpec.Code}}
+	}).Decode(&entity); err != nil {
+		return nil, err
+	}
+	return &entity, nil`
+
 const findManyTemplate = `	cursor, err := r.collection.Find(ctx, bson.M{
 {{.QuerySpec.Code}}
 	})
@@ -94,3 +94,23 @@ const findManyTemplate = `	cursor, err := r.collection.Find(ctx, bson.M{
 		return nil, err
 	}
 	return entities, nil`
+
+type mongoDeleteTemplateData struct {
+	QuerySpec querySpec
+}
+
+const deleteOneTemplate = `	result, err := r.collection.DeleteOne(ctx, bson.M{
+{{.QuerySpec.Code}}
+	})
+	if err != nil {
+		return false, err
+	}
+	return result.DeletedCount > 0, nil`
+
+const deleteManyTemplate = `	result, err := r.collection.DeleteMany(ctx, bson.M{
+{{.QuerySpec.Code}}
+	})
+	if err != nil {
+		return 0, err
+	}
+	return int(result.DeletedCount), nil`

internal/spec/models.go

@@ -33,6 +33,12 @@ type FindOperation struct {
 	Query QuerySpec
 }
 
+// DeleteOperation is a method specification for delete operations
+type DeleteOperation struct {
+	Mode  QueryMode
+	Query QuerySpec
+}
+
 // QuerySpec is a set of conditions of querying the database
 type QuerySpec struct {
 	Operator   Operator

internal/spec/parser.go

@@ -25,6 +25,8 @@ func (p interfaceMethodParser) Parse() (MethodSpec, error) {
 	switch methodNameTokens[0] {
 	case "Find":
 		return p.parseFindMethod(methodNameTokens[1:])
+	case "Delete":
+		return p.parseDeleteMethod(methodNameTokens[1:])
 	}
 	return MethodSpec{}, UnknownOperationError
 }
@@ -92,6 +94,58 @@ func (p interfaceMethodParser) extractFindReturns(returns []code.Type) (QueryMod
 	return "", UnsupportedReturnError
 }
 
+func (p interfaceMethodParser) parseDeleteMethod(tokens []string) (MethodSpec, error) {
+	if len(tokens) == 0 {
+		return MethodSpec{}, UnsupportedNameError
+	}
+
+	mode, err := p.extractDeleteReturns(p.Method.Returns)
+	if err != nil {
+		return MethodSpec{}, err
+	}
+
+	querySpec, err := p.parseQuery(tokens)
+	if err != nil {
+		return MethodSpec{}, err
+	}
+
+	if err := p.validateMethodSignature(querySpec); err != nil {
+		return MethodSpec{}, err
+	}
+
+	return MethodSpec{
+		Name:    p.Method.Name,
+		Params:  p.Method.Params,
+		Returns: p.Method.Returns,
+		Operation: DeleteOperation{
+			Mode:  mode,
+			Query: querySpec,
+		},
+	}, nil
+}
+
+func (p interfaceMethodParser) extractDeleteReturns(returns []code.Type) (QueryMode, error) {
+	if len(returns) != 2 {
+		return "", UnsupportedReturnError
+	}
+
+	if returns[1] != code.SimpleType("error") {
+		return "", UnsupportedReturnError
+	}
+
+	simpleType, ok := returns[0].(code.SimpleType)
+	if ok {
+		if simpleType == code.SimpleType("bool") {
+			return QueryModeOne, nil
+		}
+		if simpleType == code.SimpleType("int") {
+			return QueryModeMany, nil
+		}
+	}
+
+	return "", UnsupportedReturnError
+}
+
 func (p interfaceMethodParser) parseQuery(tokens []string) (QuerySpec, error) {
 	if len(tokens) == 0 {
 		return QuerySpec{}, InvalidQueryError

internal/spec/parser_test.go

@@ -40,7 +40,7 @@ type ParseInterfaceMethodTestCase struct {
 	ExpectedOutput spec.MethodSpec
 }
 
-func TestParseInterfaceMethod(t *testing.T) {
+func TestParseInterfaceMethod_Find(t *testing.T) {
 	testTable := []ParseInterfaceMethodTestCase{
 		{
 			Name: "FindOneByArg method",
@@ -470,21 +470,454 @@ func TestParseInterfaceMethod(t *testing.T) {
 	}
 }
 
+func TestParseInterfaceMethod_Delete(t *testing.T) {
+	testTable := []ParseInterfaceMethodTestCase{
+		{
+			Name: "DeleteOneByArg method",
+			Method: code.Method{
+				Name: "DeleteOneByID",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.ExternalType{PackageAlias: "primitive", Name: "ObjectID"}},
+				},
+				Returns: []code.Type{
+					code.SimpleType("bool"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedOutput: spec.MethodSpec{
+				Name: "DeleteOneByID",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.ExternalType{PackageAlias: "primitive", Name: "ObjectID"}},
+				},
+				Returns: []code.Type{
+					code.SimpleType("bool"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeOne,
+					Query: spec.QuerySpec{Predicates: []spec.Predicate{
+						{Field: "ID", Comparator: spec.ComparatorEqual},
+					}},
+				},
+			},
+		},
+		{
+			Name: "DeleteOneByMultiWordArg method",
+			Method: code.Method{
+				Name: "DeleteOneByPhoneNumber",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("string")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("bool"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedOutput: spec.MethodSpec{
+				Name: "DeleteOneByPhoneNumber",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("string")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("bool"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeOne,
+					Query: spec.QuerySpec{Predicates: []spec.Predicate{
+						{Field: "PhoneNumber", Comparator: spec.ComparatorEqual},
+					}},
+				},
+			},
+		},
+		{
+			Name: "DeleteByArg method",
+			Method: code.Method{
+				Name: "DeleteByCity",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("string")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedOutput: spec.MethodSpec{
+				Name: "DeleteByCity",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("string")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{Predicates: []spec.Predicate{
+						{Field: "City", Comparator: spec.ComparatorEqual},
+					}},
+				},
+			},
+		},
+		{
+			Name: "DeleteAll method",
+			Method: code.Method{
+				Name: "DeleteAll",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedOutput: spec.MethodSpec{
+				Name: "DeleteAll",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+				},
+			},
+		},
+		{
+			Name: "DeleteByArgAndArg method",
+			Method: code.Method{
+				Name: "DeleteByCityAndGender",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("string")},
+					{Type: code.SimpleType("Gender")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedOutput: spec.MethodSpec{
+				Name: "DeleteByCityAndGender",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("string")},
+					{Type: code.SimpleType("Gender")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{
+						Operator: spec.OperatorAnd,
+						Predicates: []spec.Predicate{
+							{Field: "City", Comparator: spec.ComparatorEqual},
+							{Field: "Gender", Comparator: spec.ComparatorEqual},
+						},
+					},
+				},
+			},
+		},
+		{
+			Name: "DeleteByArgOrArg method",
+			Method: code.Method{
+				Name: "DeleteByCityOrGender",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("string")},
+					{Type: code.SimpleType("Gender")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedOutput: spec.MethodSpec{
+				Name: "DeleteByCityOrGender",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("string")},
+					{Type: code.SimpleType("Gender")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{
+						Operator: spec.OperatorOr,
+						Predicates: []spec.Predicate{
+							{Field: "City", Comparator: spec.ComparatorEqual},
+							{Field: "Gender", Comparator: spec.ComparatorEqual},
+						},
+					},
+				},
+			},
+		},
+		{
+			Name: "DeleteByArgNot method",
+			Method: code.Method{
+				Name: "DeleteByCityNot",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("string")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedOutput: spec.MethodSpec{
+				Name: "DeleteByCityNot",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("string")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{Predicates: []spec.Predicate{
+						{Field: "City", Comparator: spec.ComparatorNot},
+					}},
+				},
+			},
+		},
+		{
+			Name: "DeleteByArgLessThan method",
+			Method: code.Method{
+				Name: "DeleteByAgeLessThan",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedOutput: spec.MethodSpec{
+				Name: "DeleteByAgeLessThan",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{Predicates: []spec.Predicate{
+						{Field: "Age", Comparator: spec.ComparatorLessThan},
+					}},
+				},
+			},
+		},
+		{
+			Name: "DeleteByArgLessThanEqual method",
+			Method: code.Method{
+				Name: "DeleteByAgeLessThanEqual",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedOutput: spec.MethodSpec{
+				Name: "DeleteByAgeLessThanEqual",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{Predicates: []spec.Predicate{
+						{Field: "Age", Comparator: spec.ComparatorLessThanEqual},
+					}},
+				},
+			},
+		},
+		{
+			Name: "DeleteByArgGreaterThan method",
+			Method: code.Method{
+				Name: "DeleteByAgeGreaterThan",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedOutput: spec.MethodSpec{
+				Name: "DeleteByAgeGreaterThan",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{Predicates: []spec.Predicate{
+						{Field: "Age", Comparator: spec.ComparatorGreaterThan},
+					}},
+				},
+			},
+		},
+		{
+			Name: "DeleteByArgGreaterThanEqual method",
+			Method: code.Method{
+				Name: "DeleteByAgeGreaterThanEqual",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedOutput: spec.MethodSpec{
+				Name: "DeleteByAgeGreaterThanEqual",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{Predicates: []spec.Predicate{
+						{Field: "Age", Comparator: spec.ComparatorGreaterThanEqual},
+					}},
+				},
+			},
+		},
+		{
+			Name: "DeleteByArgBetween method",
+			Method: code.Method{
+				Name: "DeleteByAgeBetween",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("int")},
+					{Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedOutput: spec.MethodSpec{
+				Name: "DeleteByAgeBetween",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("int")},
+					{Type: code.SimpleType("int")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{Predicates: []spec.Predicate{
+						{Field: "Age", Comparator: spec.ComparatorBetween},
+					}},
+				},
+			},
+		},
+		{
+			Name: "DeleteByArgIn method",
+			Method: code.Method{
+				Name: "DeleteByCityIn",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.ArrayType{ContainedType: code.SimpleType("string")}},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedOutput: spec.MethodSpec{
+				Name: "DeleteByCityIn",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.ArrayType{ContainedType: code.SimpleType("string")}},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+				Operation: spec.DeleteOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{Predicates: []spec.Predicate{
+						{Field: "City", Comparator: spec.ComparatorIn},
+					}},
+				},
+			},
+		},
+	}
+
+	for _, testCase := range testTable {
+		t.Run(testCase.Name, func(t *testing.T) {
+			actualSpec, err := spec.ParseInterfaceMethod(structModel, testCase.Method)
+
+			if err != nil {
+				t.Errorf("Error = %s", err)
+			}
+			if !reflect.DeepEqual(actualSpec, testCase.ExpectedOutput) {
+				t.Errorf("Expected = %v\nReceived = %v", testCase.ExpectedOutput, actualSpec)
+			}
+		})
+	}
+}
+
 type ParseInterfaceMethodInvalidTestCase struct {
 	Name          string
 	Method        code.Method
 	ExpectedError error
 }
 
-func TestParseInterfaceMethodInvalid(t *testing.T) {
+func TestParseInterfaceMethod_Invalid(t *testing.T) {
+	_, err := spec.ParseInterfaceMethod(structModel, code.Method{
+		Name: "SearchByID",
+	})
+
+	if err != spec.UnknownOperationError {
+		t.Errorf("\nExpected = %v\nReceived = %v", spec.UnknownOperationError, err)
+	}
+}
+
+func TestParseInterfaceMethod_Find_Invalid(t *testing.T) {
 	testTable := []ParseInterfaceMethodInvalidTestCase{
-		{
-			Name: "unknown operation",
-			Method: code.Method{
-				Name: "SearchByID",
-			},
-			ExpectedError: spec.UnknownOperationError,
-		},
 		{
 			Name: "unsupported find method name",
 			Method: code.Method{
@@ -657,3 +1090,178 @@ func TestParseInterfaceMethodInvalid(t *testing.T) {
 		})
 	}
 }
+
+func TestParseInterfaceMethod_Delete_Invalid(t *testing.T) {
+	testTable := []ParseInterfaceMethodInvalidTestCase{
+		{
+			Name: "unsupported delete method name",
+			Method: code.Method{
+				Name: "Delete",
+			},
+			ExpectedError: spec.UnsupportedNameError,
+		},
+		{
+			Name: "invalid number of returns",
+			Method: code.Method{
+				Name: "DeleteOneByID",
+				Returns: []code.Type{
+					code.SimpleType("UserModel"),
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedError: spec.UnsupportedReturnError,
+		},
+		{
+			Name: "unsupported return values from find method",
+			Method: code.Method{
+				Name: "DeleteOneByID",
+				Returns: []code.Type{
+					code.SimpleType("float64"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedError: spec.UnsupportedReturnError,
+		},
+		{
+			Name: "error return not provided",
+			Method: code.Method{
+				Name: "DeleteOneByID",
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("bool"),
+				},
+			},
+			ExpectedError: spec.UnsupportedReturnError,
+		},
+		{
+			Name: "misplaced operator token (leftmost)",
+			Method: code.Method{
+				Name: "DeleteByAndGender",
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedError: spec.InvalidQueryError,
+		},
+		{
+			Name: "misplaced operator token (rightmost)",
+			Method: code.Method{
+				Name: "DeleteByGenderAnd",
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedError: spec.InvalidQueryError,
+		},
+		{
+			Name: "misplaced operator token (double operator)",
+			Method: code.Method{
+				Name: "DeleteByGenderAndAndCity",
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedError: spec.InvalidQueryError,
+		},
+		{
+			Name: "ambiguous query",
+			Method: code.Method{
+				Name: "DeleteByGenderAndCityOrAge",
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedError: spec.InvalidQueryError,
+		},
+		{
+			Name: "no context parameter",
+			Method: code.Method{
+				Name: "DeleteByGender",
+				Params: []code.Param{
+					{Type: code.SimpleType("Gender")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedError: spec.ContextParamRequiredError,
+		},
+		{
+			Name: "mismatched number of parameters",
+			Method: code.Method{
+				Name: "DeleteByCountry",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("string")},
+					{Type: code.SimpleType("string")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedError: spec.InvalidParamError,
+		},
+		{
+			Name: "struct field not found",
+			Method: code.Method{
+				Name: "DeleteByCountry",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("string")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedError: spec.StructFieldNotFoundError,
+		},
+		{
+			Name: "mismatched method parameter type",
+			Method: code.Method{
+				Name: "DeleteByGender",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("string")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedError: spec.InvalidParamError,
+		},
+		{
+			Name: "mismatched method parameter type for special case",
+			Method: code.Method{
+				Name: "DeleteByCityIn",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+					{Type: code.SimpleType("string")},
+				},
+				Returns: []code.Type{
+					code.SimpleType("int"),
+					code.SimpleType("error"),
+				},
+			},
+			ExpectedError: spec.InvalidParamError,
+		},
+	}
+
+	for _, testCase := range testTable {
+		t.Run(testCase.Name, func(t *testing.T) {
+			_, err := spec.ParseInterfaceMethod(structModel, testCase.Method)
+
+			if err != testCase.ExpectedError {
+				t.Errorf("\nExpected = %v\nReceived = %v", testCase.ExpectedError, err)
+			}
+		})
+	}
+}