Allow secret test cases to use .statement and .download

spec/2025-09.md

@@ -642,12 +642,13 @@ For each test case:
 - `output_validator_args` defines arguments passed to the output validator for the test case.
 - `input_visualizer_args` defines arguments passed to the input visualizer for the test case.
 - `output_visualizer_args` defines arguments passed to the output visualizer for the test case.
-- When `full_feedback` is `true`, somebody whose submission didn't pass case should be shown:
+- When `full_feedback` is `true`, the following should be made available to a solver that didn't pass the test case:
     - the given input,
-    - the produced output (stdout),
+    - the produced output (stdout), 
     - any error messages (stderr),
     - the illustration created by the output visualizer (if applicable),
     - the expected output.
+  For a submission that fails a test case with `full_feedback` set to `true`, the relevant feedback files for that test case should be made available. These files are not made available otherwise; the rules determining which files are provided are specified in [Test Cases with Full Feedback](#test-cases-with-full-feedback).
 - `hint` provides feedback for solving a test case to, for example, somebody whose submission didn't pass.
 - `description` conveys the purpose of a test case.
   It is an explanation of what aspect or edge case of the solution the input file is meant to test.
@@ -714,11 +715,8 @@ It may be missing (for problems with no samples) or empty.
 
 #### Samples shown in the problem statement
 
-By default, the `.in` and `.ans` pairs from `data/sample` are shown in the problem statement.
-If a `.out` file exists the `.out` file is shown instead of the `.ans` file in the problem statement.
-This behavior can be customized by creating files with extension `.in.statement` and `.ans.statement`.
-If one of these files exists, its contents replaces that of the file with the same name -- except the `.statement` extension -- for purposes of the problem statement.
-Note that it is an error to provide both a `.out` and a `.ans.statement` file.
+By default, the `.in` and `.ans` pairs from `data/sample` are shown in the problem statement. This can customized by using `.out`, `.in.statement`, and `.ans.statement` files. See more in [Displayed test cases](#displayed-test-cases).
+
 
 ##### Interactive problems
 
@@ -747,12 +745,7 @@ Note that if you are using a `.interaction` file you must not provide a `.in.sta
 
 #### Samples available for download
 
-By default, the `.in`, `.ans`, and `.files` files in `data/sample` are available for download.
-Note that the content of `.in.statement` replaces that of `.in` and that the content of `.out` or `.ans.statement` replace that of `.ans` for the download.
-This behavior can be further customized by providing files with the extension `in.download` or `ans.download`.
-If one of these files exists, its contents replaces that of the file with the same name -- except the `.download` extension -- for the problem download.
-
-If you want to make other files -- like testing tools -- available for download, you can use [attachments](#attachments).
+By default, the `.in`, `.ans`, and `.files` files in `data/sample` are available for download. This can customized by using `.out`, `.in.statement`, `.ans.statement`, `.in.download`, and `.ans.download` files. See more in [Downloadable test cases](#downloadable-test-cases).
 
 #### Validation
 
@@ -766,6 +759,14 @@ However, since only the `.out` files are validated it is advised to use these if
 
 Validation can be customized by specifying `input_validator_args` and `output_validator_args` in `data/sample/test_group.yaml`.
 
+### Test Cases with Full Feedback
+
+If a test case has `full_feedback` set to `true` (see [Test Case Configuration](#test-case-configuration)), then by default, the `.in` and `.ans` pair for this particular testcase should be shown as feedback, if the submission fails this test case.
+This can customized by using `.out`, `.in.statement`, and `.ans.statement` files. See more in [Displayed test cases](#displayed-test-cases).
+
+By default, the `.in` and `.ans` files for the test cases with full feedback available for download, for the submission that fails this test case.
+This can customized by using `.out`, `.in.statement`, `.ans.statement`, `.in.download`, and `.ans.download` files. See more in [Downloadable test cases](#downloadable-test-cases).
+
 
 ## Generators
 
@@ -948,7 +949,29 @@ The system may warn when this makes other constraints redundant and should error
 
 It is required that at least one submission is used to lower bound the time limit.
 
-## Input validators
+### Priority of test case files
+
+This section summarizes which files take precedence for display and download. Each priority order defines the search order; use the first file that exists. These priorities do not affect what is executed during judging unless explicitly noted.
+
+#### Displayed test cases
+
+For samples and full-feedback test cases, the priority of displayed test cases is as follows.
+  - Input shown: `.in.statement` > `.in`.
+  - Output shown: `.out` > `.ans.statement` > `.ans`.
+Note that it is an error to have both `.out` and `.ans.statement`.
+
+For interactive and multi-pass problems, if `.interaction` exists, it is the only thing shown for the sample. Do not provide `.in.statement`, `.ans.statement`, or `.out` alongside `.interaction`.
+
+#### Downloadable test cases
+
+For the files shown to the team, if the sample or test case with full-feedback is downloaded, the priority is as follows.
+  - Input downloaded: `.in.download` > `.in.statement` > `.in`.
+  - Output downloaded: `.ans.download` > `.out` > `.ans.statement` > `.ans`.
+The `.files` files is included in downloads when present.
+
+If you want to make other files available for download, you can use [attachments](#attachments). One example of such files are testing tools.
+
+## Input Validators
 
 Input Validators, verifying the correctness of the input files, are provided in `input_validators/`.
 Input validators can be written in three formats: as a program (as specified [above](#programs)),