conf/config_test.go

package conf

import (
	"io/ioutil"
	"os"
	"testing"

	. "github.com/smartystreets/goconvey/convey"
)

type testconf struct {
	String    string
	Int       int
	Invariant string
	inUpdate  func()
}

func (t testconf) Update() {
	if t.inUpdate != nil {
		t.inUpdate()
	}
}

func TestLoadFile(t *testing.T) {
	Convey("Given a config struct", t, func() {
		c := testconf{
			String:    "default string",
			Int:       1,
			Invariant: "should not change",
		}

		Convey("Given a valid config file", func() {
			file := "test.conf"
			content := []byte(`{"String": "config string", "Int": 42}`)
			err := ioutil.WriteFile(file, content, 0o644)
			So(err, ShouldBeNil)
			defer func() { _ = os.Remove(file) }()

			Convey("When the config file is loaded", func() {
				err := LoadFile(file, &c)

				Convey("Then there is no error", func() {
					So(err, ShouldBeNil)
				})

				Convey("Then the struct fields are filled", func() {
					So(c.String, ShouldEqual, "config string")
					So(c.Int, ShouldEqual, 42)
				})

				Convey("Then the default values are kept", func() {
					So(c.Invariant, ShouldEqual, "should not change")
				})
			})
		})

		Convey("Given an invalid config file", func() {
			file := "test.conf"
			content := []byte(`String: not json`)
			err := ioutil.WriteFile(file, content, 0o644)
			So(err, ShouldBeNil)
			defer func() { _ = os.Remove(file) }()

			Convey("When the config file is loaded", func() {
				err := LoadFile(file, &c)

				Convey("Then an error is returned", func() {
					So(err, ShouldBeError)
				})

				Convey("Then the struct fields are not filled", func() {
					So(c.String, ShouldEqual, "default string")
					So(c.Int, ShouldEqual, 1)
				})
			})
		})

		Convey("Given a non existent config file", func() {
			file := "does-not-exist.conf.conf"

			Convey("When the config file is loaded", func() {
				err := LoadFile(file, &c)

				Convey("Then an error is returned", func() {
					So(err, ShouldBeError)
				})

				Convey("Then the struct fields are not filled", func() {
					So(c.String, ShouldEqual, "default string")
					So(c.Int, ShouldEqual, 1)
				})
			})
		})
	})
}

func TestSaveFile(t *testing.T) {
	Convey("Given a config struct", t, func() {
		c := testconf{
			String:    "default string",
			Int:       1,
			Invariant: "should not change",
		}

		Convey("Given a valid path", func() {
			file := "test.conf"

			Convey("When the config file is saved", func() {
				err := SaveFile(file, &c)
				defer func() { _ = os.Remove(file) }()

				Convey("Then there is no error", func() {
					So(err, ShouldBeNil)
				})

				Convey("Then the file exists", func() {
					_, err := os.Stat(file)
					So(err, ShouldBeNil)

					Convey("Then the content is correct", func() {
						expected := "{\n  \"String\": \"default string\",\n  \"Int\": 1,\n  \"Invariant\": \"should not change\"\n}"
						got, err := ioutil.ReadFile(file)
						So(err, ShouldBeNil)
						So(string(got), ShouldEqual, expected)
					})
				})
			})

			Convey("When the config file is saved with invalid data", func() {
				err := SaveFile(file, func() error { return nil })
				defer func() { _ = os.Remove(file) }()

				Convey("Then an error is returned", func() {
					So(err, ShouldBeError)
				})

				Convey("Then the file does not exist", func() {
					_, err := os.Stat(file)
					So(os.IsNotExist(err), ShouldBeTrue)
				})
			})
		})

		Convey("Given an invalid path", func() {
			file := "cannot/write/here.conf"

			Convey("When the config file is loaded", func() {
				err := SaveFile(file, &c)

				Convey("Then an error is returned", func() {
					So(err, ShouldBeError)
				})

				Convey("Then the file does not exist", func() {
					_, err := os.Stat(file)
					So(os.IsNotExist(err), ShouldBeTrue)
				})
			})
		})
	})
}

func TestLoadAndUpdateFile(t *testing.T) {
	Convey("Given a config struct and a path", t, func() {
		updated := false

		c := testconf{
			String:    "default string",
			Int:       1,
			Invariant: "should not change",
		}
		c.inUpdate = func() { updated = true }
		file := "test.conf"

		Convey("Given no file exists at this path", func() {
			_, err := os.Stat(file)
			So(err, ShouldBeError)
			So(os.IsNotExist(err), ShouldBeTrue)

			Convey("When LoadAndUpdateFile is called", func() {
				err := LoadAndUpdateFile(file, &c)
				So(err, ShouldBeNil)
				defer func() { _ = os.Remove(file) }()

				Convey("Then the config file has been created", func() {
					_, err := os.Stat(file)
					So(err, ShouldBeNil)

					Convey("and it has the default configuration", func() {
						var c2 testconf
						err := read(file, &c2)
						So(err, ShouldBeNil)
						c.inUpdate = nil
						So(c2, ShouldResemble, c)
					})
				})
			})
		})

		Convey("Given the path cannot be written", func() {
			file = "does-not-exist/test.conf"
			_, err := os.Stat(file)
			So(err, ShouldBeError)
			So(os.IsNotExist(err), ShouldBeTrue)

			Convey("When LoadAndUpdateFile is called", func() {
				err := LoadAndUpdateFile(file, &c)
				defer func() { _ = os.Remove(file) }()

				Convey("Then an error is returned", func() {
					So(err, ShouldBeError)
				})
			})
		})

		Convey("Given a config file with custom values", func() {
			content := []byte(`{"String": "config string", "Int": 42}`)
			err := ioutil.WriteFile(file, content, 0o644)
			So(err, ShouldBeNil)
			defer func() { _ = os.Remove(file) }()

			Convey("When LoadAndUpdateFile is called", func() {
				err := LoadAndUpdateFile(file, &c)

				Convey("Then there is no error", func() {
					So(err, ShouldBeNil)
				})

				Convey("Then the struct fields are filled", func() {
					So(c.String, ShouldEqual, "config string")
					So(c.Int, ShouldEqual, 42)
				})
			})
		})

		Convey("Given an invalid configuration file", func() {
			content := []byte(`String: not json`)
			err := ioutil.WriteFile(file, content, 0o644)
			So(err, ShouldBeNil)
			defer func() { _ = os.Remove(file) }()

			Convey("When LoadAndUpdateFile is called", func() {
				err := LoadAndUpdateFile(file, &c)
				defer func() { _ = os.Remove(file) }()

				Convey("Then an error is returned", func() {
					So(err, ShouldBeError)
				})
			})
		})

		Convey("Given a config file with missing options", func() {
			content := []byte(`{"String": "config string"}`)
			err := ioutil.WriteFile(file, content, 0o644)
			So(err, ShouldBeNil)
			defer func() { _ = os.Remove(file) }()

			Convey("When LoadAndUpdateFile is called", func() {
				err := LoadAndUpdateFile(file, &c)

				Convey("Then there is no error", func() {
					So(err, ShouldBeNil)
				})

				Convey("Then the config file has been updated with new options", func() {
					content, err := ioutil.ReadFile(file)
					So(err, ShouldBeNil)
					So(string(content), ShouldContainSubstring, `"Int"`)
				})
			})
		})

		Convey("Given a config file with old options", func() {
			content := []byte(`{"String": "config string", "Foo": "blah"}`)
			err := ioutil.WriteFile(file, content, 0o644)
			So(err, ShouldBeNil)
			defer func() { _ = os.Remove(file) }()

			Convey("When LoadAndUpdateFile is called", func() {
				err := LoadAndUpdateFile(file, &c)

				Convey("Then there is no error", func() {
					So(err, ShouldBeNil)
				})

				Convey("Then the config file has been updated with new options", func() {
					content, err := ioutil.ReadFile(file)
					So(err, ShouldBeNil)
					So(string(content), ShouldNotContainSubstring, `"Foo"`)
				})
			})
		})

		Convey("Given a valid config file", func() {
			content := []byte(`{"String": "config string"}`)
			err := ioutil.WriteFile(file, content, 0o644)
			So(err, ShouldBeNil)
			defer func() { _ = os.Remove(file) }()

			Convey("When LoadAndUpdateFile is called", func() {
				err := LoadAndUpdateFile(file, &c)

				Convey("Then there is no error", func() {
					So(err, ShouldBeNil)
				})

				Convey("Then the update method of the struct has been called", func() {
					So(updated, ShouldBeTrue)
				})
			})
		})
	})
}