Add SetExclude function and tests

options.go

@@ -71,11 +71,16 @@ const (
 	OrderDescending order = "desc"
 )
 
+// SetOrder is a functional option used to sort the results from an API call.
+// The default order is by relevance.
+//
+// For more information, visit: https://api-docs.igdb.com/#sorting
 func SetOrder(field string, order order) Option {
 	return func() (apicalypse.Option, error) {
 		if whitespace.IsBlank(field) {
 			return nil, ErrEmptyFields
 		}
+
 		return apicalypse.Sort(field, string(order)), nil
 	}
 }
@@ -115,24 +120,45 @@ func SetOffset(off int) Option {
 // match an IGDB object's JSON field tag exactly, not the Go struct field
 // name.
 //
-// The default for Get and List functions is set to all available fields.
-// The default for Search functions is set to solely the ID field.
-//
 // For more information, visit: https://api-docs.igdb.com/#fields
 func SetFields(fields ...string) Option {
 	return func() (apicalypse.Option, error) {
 		if len(fields) <= 0 {
 			return nil, ErrEmptyFields
 		}
+
 		for _, f := range fields {
 			if whitespace.IsBlank(f) {
 				return nil, ErrEmptyFields
 			}
 		}
+
 		return apicalypse.Fields(fields...), nil
 	}
 }
 
+// SetExclude is a functional option used to specify which fields of the
+// requested IGDB object you want the API to exclude. Note that the field
+// string must match an IGDB object's JSON field tag exactly, not the Go struct
+// name.
+//
+// For more information, visit: https://api-docs.igdb.com/#exclude
+func SetExclude(fields ...string) Option {
+	return func() (apicalypse.Option, error) {
+		if len(fields) <= 0 {
+			return nil, ErrEmptyFields
+		}
+
+		for _, f := range fields {
+			if whitespace.IsBlank(f) {
+				return nil, ErrEmptyFields
+			}
+		}
+
+		return apicalypse.Exclude(fields...), nil
+	}
+}
+
 // operator represents the postfix operation used to filter the results from
 // an API call using the provided field value. For the list of postfix
 // operators, visit: https://api-docs.igdb.com/#filters
@@ -201,6 +227,7 @@ func setSearch(qry string) Option {
 		if whitespace.IsBlank(qry) {
 			return nil, ErrEmptyQry
 		}
+
 		return apicalypse.Search("", qry), nil
 	}
 }

options_test.go

@@ -194,6 +194,44 @@ func TestSetFields(t *testing.T) {
 	}
 }
 
+func TestSetExclude(t *testing.T) {
+	var tests = []struct {
+		name       string
+		fields     []string
+		wantFields string
+		wantErr    error
+	}{
+		{"Single non-empty field", []string{"name"}, "name", nil},
+		{"Multiple non-empty fields", []string{"name", "popularity", "rating"}, "name,popularity,rating", nil},
+		{"Empty fields slice", []string{}, "", ErrEmptyFields},
+		{"Single empty field", []string{"  "}, "", ErrEmptyFields},
+		{"Multiple empty fields", []string{"", " ", "", ""}, "", ErrEmptyFields},
+		{"Mixed empty and non-empty fields", []string{"", "id", "  ", "url"}, "", ErrEmptyFields},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			fn, err := SetExclude(test.fields...)()
+			if errors.Cause(err) != test.wantErr {
+				t.Errorf("got: <%v>, want: <%v>", errors.Cause(err), test.wantErr)
+			}
+
+			if test.wantErr != nil {
+				return
+			}
+
+			q, err := apicalypse.Query(fn)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if !strings.Contains(q, test.wantFields) {
+				t.Errorf("got: <%v>, want: <%v>", q, test.wantFields)
+			}
+		})
+	}
+}
+
 func TestSetFilter(t *testing.T) {
 	var tests = []struct {
 		name       string