fix issue OpenAPITools#12738 (OpenAPITools#13495)

Co-authored-by: Christopher Thonfeld-Guckes <[email protected]>
jblakeney · Oct 19, 2022 · a3fbb82 · a3fbb82
1 parent 11c43c3
commit a3fbb82
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Showing 2 changed files with 27 additions and 1 deletion.
diff --git a/...generator/src/main/java/org/openapitools/codegen/templating/mustache/TitlecaseLambda.java b/...generator/src/main/java/org/openapitools/codegen/templating/mustache/TitlecaseLambda.java
@@ -61,7 +61,15 @@ public TitlecaseLambda(String delimiter) {
     }
 
     private String titleCase(final String input) {
-        return input.substring(0, 1).toUpperCase(Locale.ROOT) + input.substring(1);
+        if(input == null || "".equals(input)){
+            return "";
+        }
+
+        String firstLetter = input.substring(0, 1).toUpperCase(Locale.ROOT);
+        if (input.length() == 1) {
+            return firstLetter;
+        }
+        return firstLetter + input.substring(1);
     }
 
     @Override

diff --git a/...rator/src/test/java/org/openapitools/codegen/templating/mustache/TitlecaseLambdaTest.java b/...rator/src/test/java/org/openapitools/codegen/templating/mustache/TitlecaseLambdaTest.java
@@ -15,6 +15,24 @@ public void titlecaseTest() {
         test("Once Upon A Time", "{{#titlecase}}once upon a time{{/titlecase}}", ctx);
     }
 
+    @Test
+    public void titlecaseSingleLetterTest() {
+        // Given
+        Map<String, Object> ctx = context("titlecase", new TitlecaseLambda());
+
+        // When & Then
+        test("O", "{{#titlecase}}o{{/titlecase}}", ctx);
+    }
+
+    @Test
+    public void titlecaseEmptyStringTest() {
+        // Given
+        Map<String, Object> ctx = context("titlecase", new TitlecaseLambda());
+
+        // When & Then
+        test("", "{{#titlecase}}{{/titlecase}}", ctx);
+    }
+
     @Test
     public void titlecaseWithDelimiterTest() {
         // Given