diff --git a/tests/scripts/generate_test_code.py b/tests/scripts/generate_test_code.py
index f5750aa..6d65986 100755
--- a/tests/scripts/generate_test_code.py
+++ b/tests/scripts/generate_test_code.py
@@ -126,33 +126,33 @@
 This script replaces following fields in the template and generates
 the test source file:
 
-$test_common_helpers        <-- All common code from helpers.function
-                                is substituted here.
-$functions_code             <-- Test functions are substituted here
-                                from the input test_suit_xyz.function
-                                file. C preprocessor checks are generated
-                                for the build dependencies specified
-                                in the input file. This script also
-                                generates wrappers for the test
-                                functions with code to expand the
-                                string parameters read from the data
-                                file.
-$expression_code            <-- This script enumerates the
-                                expressions in the .data file and
-                                generates code to handle enumerated
-                                expression Ids and return the values.
-$dep_check_code             <-- This script enumerates all
-                                build dependencies and generate
-                                code to handle enumerated build
-                                dependency Id and return status: if
-                                the dependency is defined or not.
-$dispatch_code              <-- This script enumerates the functions
-                                specified in the input test data file
-                                and generates the initializer for the
-                                function table in the template
-                                file.
-$platform_code              <-- Platform specific setup and test
-                                dispatch code.
+__MBEDTLS_TEST_TEMPLATE__TEST_COMMON_HELPERS    <-- All common code from helpers.function
+                                                    is substituted here.
+__MBEDTLS_TEST_TEMPLATE__FUNCTIONS_CODE         <-- Test functions are substituted here
+                                                    from the input test_suit_xyz.function
+                                                    file. C preprocessor checks are generated
+                                                    for the build dependencies specified
+                                                    in the input file. This script also
+                                                    generates wrappers for the test
+                                                    functions with code to expand the
+                                                    string parameters read from the data
+                                                    file.
+__MBEDTLS_TEST_TEMPLATE__EXPRESSION_CODE        <-- This script enumerates the
+                                                    expressions in the .data file and
+                                                    generates code to handle enumerated
+                                                    expression Ids and return the values.
+__MBEDTLS_TEST_TEMPLATE__DEP_CHECK_CODE         <-- This script enumerates all
+                                                    build dependencies and generate
+                                                    code to handle enumerated build
+                                                    dependency Id and return status: if
+                                                    the dependency is defined or not.
+__MBEDTLS_TEST_TEMPLATE__DISPATCH_CODE          <-- This script enumerates the functions
+                                                    specified in the input test data file
+                                                    and generates the initializer for the
+                                                    function table in the template
+                                                    file.
+__MBEDTLS_TEST_TEMPLATE__PLATFORM_CODE          <-- Platform specific setup and test
+                                                    dispatch code.
 
 """
 
@@ -974,11 +974,30 @@
     :param snippets: Generated and code snippets
     :return:
     """
+
+    # Create a placeholder pattern with the correct named capture groups
+    # to override the default provided with Template.
+    # Match nothing (no way of escaping placeholders).
+    escaped = "(?P<escaped>(?!))"
+    # Match the "__MBEDTLS_TEST_TEMPLATE__PLACEHOLDER_NAME" pattern.
+    named = "__MBEDTLS_TEST_TEMPLATE__(?P<named>[A-Z][_A-Z0-9]*)"
+    # Match nothing (no braced placeholder syntax).
+    braced = "(?P<braced>(?!))"
+    # If not already matched, a "__MBEDTLS_TEST_TEMPLATE__" prefix is invalid.
+    invalid = "(?P<invalid>__MBEDTLS_TEST_TEMPLATE__)"
+    placeholder_pattern = re.compile(escaped \
+            + "|" + named \
+            + "|" + braced \
+            + "|" + invalid)
+
     with open(template_file, 'r') as template_f, open(c_file, 'w') as c_f:
         for line_no, line in enumerate(template_f.readlines(), 1):
             # Update line number. +1 as #line directive sets next line number
             snippets['line_no'] = line_no + 1
-            code = string.Template(line).substitute(**snippets)
+            template = string.Template(line)
+            template.pattern = placeholder_pattern
+            snippets = {k.upper():v for (k, v) in snippets.items()}
+            code = template.substitute(**snippets)
             c_f.write(code)
 
 
diff --git a/tests/suites/main_test.function b/tests/suites/main_test.function
index ac00f45..65c7083 100644
--- a/tests/suites/main_test.function
+++ b/tests/suites/main_test.function
@@ -3,17 +3,17 @@
  * *** THIS FILE HAS BEEN MACHINE GENERATED ***
  *
  * This file has been machine generated using the script:
- * $generator_script
+ * __MBEDTLS_TEST_TEMPLATE__GENERATOR_SCRIPT
  *
- * Test file      : $test_file
+ * Test file      : __MBEDTLS_TEST_TEMPLATE__TEST_FILE
  *
  * The following files were used to create this file.
  *
- *      Main code file      : $test_main_file
- *      Platform code file  : $test_platform_file
- *      Helper file         : $test_common_helper_file
- *      Test suite file     : $test_case_file
- *      Test suite data     : $test_case_data_file
+ *      Main code file      : __MBEDTLS_TEST_TEMPLATE__TEST_MAIN_FILE
+ *      Platform code file  : __MBEDTLS_TEST_TEMPLATE__TEST_PLATFORM_FILE
+ *      Helper file         : __MBEDTLS_TEST_TEMPLATE__TEST_COMMON_HELPER_FILE
+ *      Test suite file     : __MBEDTLS_TEST_TEMPLATE__TEST_CASE_FILE
+ *      Test suite data     : __MBEDTLS_TEST_TEMPLATE__TEST_CASE_DATA_FILE
  *
  */
 
@@ -49,9 +49,9 @@
 /*----------------------------------------------------------------------------*/
 /* Common helper code */
 
-$test_common_helpers
+__MBEDTLS_TEST_TEMPLATE__TEST_COMMON_HELPERS
 
-#line $line_no "suites/main_test.function"
+#line __MBEDTLS_TEST_TEMPLATE__LINE_NO "suites/main_test.function"
 
 
 /*----------------------------------------------------------------------------*/
@@ -60,9 +60,9 @@
 
 #define TEST_SUITE_ACTIVE
 
-$functions_code
+__MBEDTLS_TEST_TEMPLATE__FUNCTIONS_CODE
 
-#line $line_no "suites/main_test.function"
+#line __MBEDTLS_TEST_TEMPLATE__LINE_NO "suites/main_test.function"
 
 
 /*----------------------------------------------------------------------------*/
@@ -74,7 +74,7 @@
  *              For optimizing space for embedded targets each expression/macro
  *              is identified by a unique identifier instead of string literals.
  *              Identifiers and evaluation code is generated by script:
- *              $generator_script
+ *              __MBEDTLS_TEST_TEMPLATE__GENERATOR_SCRIPT
  *
  * \param exp_id    Expression identifier.
  * \param out_value Pointer to int to hold the integer.
@@ -90,8 +90,8 @@
 
     switch( exp_id )
     {
-$expression_code
-#line $line_no "suites/main_test.function"
+__MBEDTLS_TEST_TEMPLATE__EXPRESSION_CODE
+#line __MBEDTLS_TEST_TEMPLATE__LINE_NO "suites/main_test.function"
         default:
            {
                 ret = KEY_VALUE_MAPPING_NOT_FOUND;
@@ -107,7 +107,7 @@
  *              For optimizing space for embedded targets each dependency
  *              is identified by a unique identifier instead of string literals.
  *              Identifiers and check code is generated by script:
- *              $generator_script
+ *              __MBEDTLS_TEST_TEMPLATE__GENERATOR_SCRIPT
  *
  * \param dep_id    Dependency identifier.
  *
@@ -121,8 +121,8 @@
 
     switch( dep_id )
     {
-$dep_check_code
-#line $line_no "suites/main_test.function"
+__MBEDTLS_TEST_TEMPLATE__DEP_CHECK_CODE
+#line __MBEDTLS_TEST_TEMPLATE__LINE_NO "suites/main_test.function"
         default:
             break;
     }
@@ -149,13 +149,13 @@
 /**
  * \brief       Table of test function wrappers. Used by dispatch_test().
  *              This table is populated by script:
- *              $generator_script
+ *              __MBEDTLS_TEST_TEMPLATE__GENERATOR_SCRIPT
  *
  */
 TestWrapper_t test_funcs[] =
 {
-$dispatch_code
-#line $line_no "suites/main_test.function"
+__MBEDTLS_TEST_TEMPLATE__DISPATCH_CODE
+#line __MBEDTLS_TEST_TEMPLATE__LINE_NO "suites/main_test.function"
 };
 
 /**
@@ -265,9 +265,9 @@
 }
 
 
-$platform_code
+__MBEDTLS_TEST_TEMPLATE__PLATFORM_CODE
 
-#line $line_no "suites/main_test.function"
+#line __MBEDTLS_TEST_TEMPLATE__LINE_NO "suites/main_test.function"
 
 /*----------------------------------------------------------------------------*/
 /* Main Test code */