test(db): add test coverage

interview/db/db_test.go

@@ -2,6 +2,8 @@ package db_test
 
 import (
 	"fmt"
+	"reflect"
+	"testing"
 	"time"
 
 	"github.com/eng618/go-eng/interview/db"
@@ -10,21 +12,92 @@ import (
 func Example() {
 	db := db.NewDatabase()
 
-	db.Set("foo", "bar")
+	t := db.Set("foo", "bar")
 	fmt.Println("just set foo to:", db.Get("foo"))
 
 	db.Set("foo", "baz")
 	fmt.Println("the latest foo is:", db.Get("foo"))
 
-	// DB can set ints also
+	// You can use the common ok idiom to get a key with a particular time stamp.
+	if val, ok := db.GetForTime("foo", t); ok {
+		fmt.Println("the foo at", t, ":", val)
+	}
+
 	db.Set("age", 36)
 	age := db.Get("age")
 	fmt.Println("the age in database is:", age)
 
-	// You can use the common ok idiom to get a key with a particular time stamp.
-	if val, ok := db.GetForTime("foo", time.Now()); ok {
-		fmt.Println(val)
+	db.Print()
+}
+
+func getTestDatabase() *db.InMemDB {
+	db := db.NewDatabase()
+	db.Set("foo", "bar")
+	db.Set("hello", "world")
+	return db
+}
+
+func TestNewDatabase(t *testing.T) {
+	if got := db.NewDatabase(); got == nil {
+		t.Errorf("NewDatabase() = %v, wanted not nil", got)
+	}
+}
+
+func TestInMemDB_Set(t *testing.T) {
+	db := getTestDatabase()
+	if got := db.Get("foo"); got != "bar" {
+		t.Error("Failed to get foo")
+	}
+}
+
+func TestInMemDB_Set_multipleValuesForKey(t *testing.T) {
+	db := getTestDatabase()
+	if got := db.Get("foo"); got != "bar" {
+		t.Error("Failed to get foo")
 	}
+}
+
+func TestInMemDB_Get_basic(t *testing.T) {
+	db := getTestDatabase()
+	// foo originally set in getTestDatabase(), set an additional value
+	db.Set("foo", "baz")
+	if got := db.Get("foo"); got != "baz" {
+		t.Error("Failed to get foo")
+	}
+}
+
+func TestInMemDB_Get_noValue(t *testing.T) {
+	db := getTestDatabase()
+	if got := db.Get("none"); got != nil {
+		t.Error("Failed to get foo")
+	}
+}
+
+func TestInMemDB_GetForTime(t *testing.T) {
+	db := getTestDatabase()
+	setTime := db.Set("test", "testValue")
+	defaultTimeType := reflect.ValueOf(time.Now())
+	setTimeType := reflect.ValueOf(setTime)
+
+	if defaultTimeType != setTimeType {
+		t.Error("Failed, did not get a set time.")
+	}
+
+	if v, ok := db.GetForTime("test", setTime); ok {
+		if v != "testValue" {
+			t.Error("Failed, returned the wrong value.")
+		}
+	}
+}
+
+func TestInMemDB_GetForTime_noValue(t *testing.T) {
+	db := getTestDatabase()
+	if v, ok := db.GetForTime("foo", time.Now()); ok && v != nil {
+		t.Error("this should be nil")
+	}
+}
 
+func TestInMemDB_Print(t *testing.T) {
+	db := getTestDatabase()
 	db.Print()
 }