test: add variantOffsets tests for getTolgeePlurals

src/parser/getTolgeePlurals.test.ts

@@ -28,4 +28,72 @@ describe("get tolgee plurals", () => {
   it("ignores tags, when parsing plurals", () => {
     shouldBePlural("{value, plural, other {# '< tests} one {# test} }");
   });
+
+  describe("variantOffsets", () => {
+    function expectOffsetMatchesVariant(
+      input: string,
+      variant: Intl.LDMLPluralRule,
+      raw = false
+    ) {
+      const result = getTolgeePlurals(input, raw);
+      const text = result.variants[variant]!;
+      const offset = result.variantOffsets?.[variant];
+      expect(offset).toBeDefined();
+      // When raw=false, variant text is the raw substring, so offset must match
+      if (!raw) {
+        expect(input.substring(offset!, offset! + text.length)).toBe(text);
+      }
+    }
+
+    it("returns correct offsets for simple plural", () => {
+      const input = "{variable, plural, one {test} other {rest}}";
+      expectOffsetMatchesVariant(input, "one");
+      expectOffsetMatchesVariant(input, "other");
+    });
+
+    it("returns correct offsets for plural with three variants", () => {
+      const input =
+        "{count, plural, one {# item} few {# items} other {# items}}";
+      expectOffsetMatchesVariant(input, "one");
+      expectOffsetMatchesVariant(input, "few");
+      expectOffsetMatchesVariant(input, "other");
+    });
+
+    it("returns correct offsets with escaped content", () => {
+      const input = "{variable, plural, one {'{'} other {rest}}";
+      expectOffsetMatchesVariant(input, "one");
+      expectOffsetMatchesVariant(input, "other");
+    });
+
+    it("returns offsets in raw mode", () => {
+      const input = "{variable, plural, one {hello} other {world}}";
+      const result = getTolgeePlurals(input, true);
+      expect(result.variantOffsets).toBeDefined();
+      // Simple text with no escapes — offset should still be consistent
+      expectOffsetMatchesVariant(input, "one", true);
+      expectOffsetMatchesVariant(input, "other", true);
+    });
+
+    it("does not return variantOffsets for non-plural input", () => {
+      const result = getTolgeePlurals("just a plain string", false);
+      expect(result.variantOffsets).toBeUndefined();
+    });
+
+    it("does not return variantOffsets for select (non-plural) expression", () => {
+      const result = getTolgeePlurals(
+        "{gender, select, male {He} female {She} other {They}}",
+        false
+      );
+      expect(result.variantOffsets).toBeUndefined();
+    });
+
+    it("returns offset for empty variant content", () => {
+      const input = "{variable, plural, one {test} other {}}";
+      const result = getTolgeePlurals(input, false);
+      expect(result.variantOffsets).toBeDefined();
+      expectOffsetMatchesVariant(input, "one");
+      // Empty variant — offset should still be defined
+      expect(result.variantOffsets!.other).toBeDefined();
+    });
+  });
 });