1 files changed, 72 insertions, 0 deletions
diff --git a/internal/plan_test.go b/internal/plan_test.go
new file mode 100644
index 0000000..827c6e4
--- /dev/null
+++ b/internal/plan_test.go
@@ -0,0 +1,72 @@
+// SPDX-FileCopyrightText: 2026 Stefan Majewsky <majewsky@gmx.net>
+// SPDX-License-Identifier: Apache-2.0
+
+package internal_test
+
+import (
+	"reflect"
+	"testing"
+	"time"
+
+	"go.xyrillian.de/oblast/info"
+	"go.xyrillian.de/oblast/internal"
+	"go.xyrillian.de/oblast/internal/assert"
+)
+
+func TestPlanFieldTraversal(t *testing.T) {
+	type Log struct {
+		info.TableNameIs  `db:"log_entries"`
+		info.PrimaryKeyIs `db:"id"`
+		ID                int64     `db:"id,auto"`
+		CreatedAt         time.Time `db:"created_at"`
+		Message           string    `db:"message"`
+		private1          bool      `db:"private1"` //nolint:unused
+	}
+
+	// assert on interface implementations
+	var (
+		_ info.IsTable               = Log{}
+		_ info.IsTableWithPrimaryKey = Log{}
+	)
+
+	// check that the plan for Log:
+	// 1. has no IndexByColumnName entries for marker types
+	// 2. ignores "private1" because it cannot be written through reflection
+	// 3. recognizes "id" as an autofilled column
+	plan, err := internal.BuildPlan(reflect.TypeFor[Log](), internal.PostgresDialect{})
+	if err != nil {
+		t.Error(err)
+	}
+	assert.Equal(t, plan.TableName, "log_entries")
+	assert.DeepEqual(t, plan.PrimaryKeyColumns, []string{"id"})
+	assert.DeepEqual(t, plan.AutoColumns, []string{"id"})
+	assert.DeepEqual(t, plan.IndexByColumnName, map[string][]int{
+		"id":         {2},
+		"created_at": {3},
+		"message":    {4},
+	})
+
+	type record struct {
+		Log
+		Keks     bool `db:"keks"`
+		private2 bool `db:"private2"` //nolint:unused
+	}
+
+	// check that the plan for record:
+	// 1. works at all, even though it as a whole is an unexported type
+	// 2. traverses into Log and includes all of its fields as well
+	// 3. completely ignores the marker types in type Log
+	plan, err = internal.BuildPlan(reflect.TypeFor[record](), internal.PostgresDialect{})
+	if err != nil {
+		t.Error(err)
+	}
+	assert.Equal(t, plan.TableName, "")
+	assert.DeepEqual(t, plan.PrimaryKeyColumns, nil)
+	assert.DeepEqual(t, plan.AutoColumns, []string{"id"}) // this is okay, it does not bear significance in practice since no queries are generated
+	assert.DeepEqual(t, plan.IndexByColumnName, map[string][]int{
+		"id":         {0, 2},
+		"created_at": {0, 3},
+		"message":    {0, 4},
+		"keks":       {1},
+	})
+}