Fix escaping issue in filterExpression for RedisVectorStore file name filtering

Author: kmw10693

spring-ai-vector-store/src/test/java/org/springframework/ai/vectorstore/filter/SearchRequestTests.java

@@ -138,6 +138,61 @@ public void filterExpression() {
 
 }
 
+@Test
+public void filterExpressionWithDotAndBackslashIsEscaped() {
+var request = SearchRequest.builder()
+.query("Test")
+.filterExpression("file_name == 'clean.code.pdf' && path == 'C:\\docs\\files'")
+.build();
+
+var expression = request.getFilterExpression();
+
+assertThat(expression.toString()).contains("clean\\.code\\.pdf");
+assertThat(expression.toString()).contains("C:\\\\docs\\\\files");
+}
+
+@Test
+public void filterExpressionWithMultipleLiteralsIsEscapedIndependently() {
+var request = SearchRequest.builder()
+.query("Test")
+.filterExpression("file_name == 'a.b.c' && author == 'me.you'")
+.build();
+
+var expression = request.getFilterExpression();
+
+assertThat(expression.toString()).contains("a\\.b\\.c");
+assertThat(expression.toString()).contains("me\\.you");
+}
+
+@Test
+public void filterExpressionWithVariousFileExtensionsIsEscaped() {
+var request = SearchRequest.builder()
+.query("Test")
+.filterExpression(
+"file_name == 'summary.epub' || file_name == 'lecture_notes.md' || file_name == 'slides.pptx'")
+.build();
+
+String expression = request.getFilterExpression().toString();
+
+assertThat(expression).contains("summary\\.epub");
+assertThat(expression).contains("lecture_notes\\.md");
+assertThat(expression).contains("slides\\.pptx");
+}
+
+@Test
+public void filterExpressionWithInListIsEscaped() {
+var request = SearchRequest.builder()
+.query("Test")
+.filterExpression("file_name IN ['a.pdf', 'b.txt', 'final.report.docx']")
+.build();
+
+String expression = request.getFilterExpression().toString();
+
+assertThat(expression).contains("a\\.pdf");
+assertThat(expression).contains("b\\.txt");
+assertThat(expression).contains("final\\.report\\.docx");
+}
+
 private void checkDefaults(SearchRequest request) {
 assertThat(request.getFilterExpression()).isNull();
 assertThat(request.getSimilarityThreshold()).isEqualTo(SearchRequest.SIMILARITY_THRESHOLD_ACCEPT_ALL);