From 5ba38a82814985dbff66ad38db3094098c046cf3 Mon Sep 17 00:00:00 2001
From: Lilleman auf Larv <lilleman@larvit.se>
Date: Thu, 3 Sep 2026 17:27:51 +0200
Subject: [PATCH] Tests for FakeTemplate: inline format strings, JSON
 templates, references, and their errors

---
 faketemplate_test.go | 106 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 faketemplate_test.go

diff --git a/faketemplate_test.go b/faketemplate_test.go
new file mode 100644
index 0000000..4b0bb1c
--- /dev/null
+++ b/faketemplate_test.go
@@ -0,0 +1,106 @@
+package fejkdata
+
+import (
+	"strings"
+	"testing"
+)
+
+func tmpl(t *testing.T, f *Generator, input string) string {
+	t.Helper()
+	s, err := f.FakeTemplate(input)
+	if err != nil {
+		t.Fatalf("FakeTemplate(%q): %v", input, err)
+	}
+	return s
+}
+
+func shipped(t *testing.T, opts ...Option) *Generator {
+	t.Helper()
+	f, err := New(append([]Option{WithSeed(1)}, opts...)...)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return f
+}
+
+func TestFakeTemplateFormatString(t *testing.T) {
+	f := shipped(t)
+	got := tmpl(t, f, "name: {/sv_SE.person.last}")
+	if !strings.HasPrefix(got, "name: ") || strings.HasSuffix(got, " ") || strings.Contains(got, "{") {
+		t.Fatalf("FakeTemplate = %q, want a rendered last name after the prefix", got)
+	}
+}
+
+func TestFakeTemplateJSONObject(t *testing.T) {
+	f := shipped(t)
+	seen := map[string]bool{}
+	for i := 0; i < 50; i++ {
+		seen[tmpl(t, f, `{"format":"name: {x}","x":["bosse","lina"]}`)] = true
+	}
+	if !seen["name: bosse"] || !seen["name: lina"] || len(seen) != 2 {
+		t.Fatalf("JSON template produced %v, want both names", seen)
+	}
+}
+
+func TestFakeTemplateJSONArray(t *testing.T) {
+	f := shipped(t)
+	seen := map[string]bool{}
+	for i := 0; i < 50; i++ {
+		seen[tmpl(t, f, `["foo","bar","baz"]`)] = true
+	}
+	if len(seen) != 3 {
+		t.Fatalf("JSON array choice produced %v, want three items", seen)
+	}
+}
+
+func TestFakeTemplateCorrelatedReferences(t *testing.T) {
+	dir := writeData(t, map[string]string{
+		"person": `[{"format":"{first} {last}","first":"Ada","last":"Lovelace"},{"format":"{first} {last}","first":"Bo","last":"Ek"}]`,
+	})
+	f := newGenerator(t, dir, WithSeed(1))
+	for i := 0; i < 100; i++ {
+		got := tmpl(t, f, "{/person.first} {/person.last}")
+		if got != "Ada Lovelace" && got != "Bo Ek" {
+			t.Fatalf("correlated references = %q, want one person's first and last", got)
+		}
+	}
+}
+
+func TestFakeTemplateDeterministic(t *testing.T) {
+	a, b := shipped(t), shipped(t)
+	for i := 0; i < 20; i++ {
+		in := "row: {/misc.uuid} {digits(3)}"
+		if x, y := tmpl(t, a, in), tmpl(t, b, in); x != y {
+			t.Fatalf("same seed diverged: %q != %q", x, y)
+		}
+	}
+}
+
+func TestFakeTemplateErrors(t *testing.T) {
+	f := shipped(t)
+	for _, c := range []struct {
+		input string
+		want  string
+	}{
+		{`{"x":"Q"}`, "missing string \"format\""},
+		{`"{x}"`, `no field "x"`},
+		{`"{digits(0)}"`, "must be positive"},
+		{`name: {/no.such.path}`, "no entry"},
+		{`name: {..nope}`, "no folder above"},
+		{`{"format":"x"}`, "is a string"},
+		{`{/misc.country} {/misc.country.alpha2}`, "renders a level"},
+	} {
+		_, err := f.FakeTemplate(c.input)
+		if err == nil || !strings.Contains(err.Error(), c.want) {
+			t.Errorf("FakeTemplate(%q) = %v, want an error containing %q", c.input, err, c.want)
+		}
+	}
+}
+
+func TestFakeTemplateRepeatBound(t *testing.T) {
+	f := shipped(t)
+	_, err := f.FakeTemplate(`{"format":"{x}","repeat":200,"x":{"format":"{y}","repeat":200,"y":{"format":"z","repeat":200}}}`)
+	if err == nil || !strings.Contains(err.Error(), "maximum") {
+		t.Errorf("nested repeat over the cap = %v, want it rejected naming the maximum", err)
+	}
+}