Add tests for db initialisation

todo-go/database/database_test.go

@@ -0,0 +1,32 @@
+package database
+
+import (
+	"os"
+	"testing"
+)
+
+func TestInitialiseDB(t *testing.T) {
+	path, err := os.CreateTemp("", "tmp.json")
+	if err != nil {
+		panic(err)
+	}
+	defer os.Remove(path.Name())
+
+	InitialiseDB(path.Name())
+	result, err := os.ReadFile(path.Name())
+	if err != nil {
+		t.Fatalf("Failed to read from %s; %v", path.Name(), err)
+	}
+	resultString := string(result)
+	want := "[]"
+	if resultString != want {
+		t.Fatalf("InitialiseDB() wrote %s; want %s", resultString, want)
+	}
+}
+
+func TestInitialiseDBErrors(t *testing.T) {
+	err := InitialiseDB("~/fail.json")
+	if err == nil {
+		t.Fatalf("InitialiseDB(\"~/fail.json\") gave nil error; want non-nill error")
+	}
+}