Add stage descriptions for fetch extension

course-definition.yml

@@ -705,7 +705,6 @@ stages:
       - The correlation ID in the response header matches the correlation ID in the request header.
       - The error code in the response body is `0` (No Error).
       - The `throttle_time_ms` field in the response is present (any value is accepted).
-      - The `session_id` field in the response is `0`.
       - The `responses` field in the response has 1 element, and in that element:
         - The `topic_id` field matches what was sent in the request.
         - The `partitions` array has 1 element, and in that element:
@@ -723,18 +722,79 @@ stages:
   - slug: "cm4"
     primary_extension_slug: "consuming-messages"
     name: "Fetch with an empty topic"
-    difficulty: hard
+    difficulty: medium
     description_md: |-
-      🚧 **We're still working on tests for this stage!**.
+      In this stage, you'll implement the Fetch response for a topic with no messages.
+
+      🚧 **We're still working on instructions for this stage**. You can find notes on how the tester works below.
+
+      In the meantime, please use
+      [this link](https://forum.codecrafters.io/new-topic?category=Challenges&tags=challenge%3Akafka&title=Question+about+cm4%3A+Fetch+with+an+empty+topic&body=%3Cyour+question+here%3E)
+      to ask questions on the forum.
+
+      ### Tests
+
+      The tester will execute your program like this:
+
+      ```bash
+      $ ./your_program.sh
+      ```
+
+      It'll then connect to your server on port 9092 and send a `Fetch` (v16) request. The request will contain a single topic with a topic ID that exists. However, the topic has no messages assigned to it (i.e. the log file is empty).
+
+      The tester will validate that:
+
+      - The first 4 bytes of your response (the "message length") are valid.
+      - The correlation ID in the response header matches the correlation ID in the request header.
+      - The error code in the response body is `0` (No Error).
+      - The `throttle_time_ms` field in the response is present (any value is accepted).
+      - The `responses` field in the response has 1 element, and in that element:
+        - The `topic_id` field matches what was sent in the request.
+        - The `partitions` array has 1 element, and in that element:
+          - The `partition_index` field is `0`.
+          - The `error_code` field is `0` (No Error).
+          - The `records` array has `0` elements.
+
     marketing_md: |-
-      In this stage, you'll implement the Fetch response for a topic with multiple messages.
+      In this stage, you'll implement the Fetch response for a topic with no messages.
 
   - slug: "eg2"
     primary_extension_slug: "consuming-messages"
     name: "Fetch single message from disk"
     difficulty: hard
     description_md: |-
-      🚧 **We're still working on tests for this stage!**.
+      In this stage, you'll implement the Fetch response for a topic with a single message, reading it from disk.
+
+      🚧 **We're still working on instructions for this stage**. You can find notes on how the tester works below.
+
+      In the meantime, please use
+      [this link](https://forum.codecrafters.io/new-topic?category=Challenges&tags=challenge%3Akafka&title=Question+about+eg2%3A+Fetch+single+message+from+disk&body=%3Cyour+question+here%3E)
+      to ask questions on the forum.
+
+      ### Tests
+
+      The tester will execute your program like this:
+
+      ```bash
+      $ ./your_program.sh
+      ```
+
+      It'll then connect to your server on port 9092 and send a `Fetch` (v16) request. The request will contain a single topic with a topic ID that exists. The topic has a single message assigned to it.
+
+      The tester will validate that:
+
+      - The first 4 bytes of your response (the "message length") are valid.
+      - The correlation ID in the response header matches the correlation ID in the request header.
+      - The error code in the response body is `0` (No Error).
+      - The `throttle_time_ms` field in the response is present (any value is accepted).
+      - The `responses` field in the response has 1 element, and in that element:
+        - The `topic_id` field matches what was sent in the request.
+        - The `partitions` array has 1 element, and in that element:
+          - The `partition_index` field is `0`.
+          - The `error_code` field is `0` (No Error).
+          - The `records` array has 1 element.
+            - The entire `RecordBatch` content is read from disk. (We will compare the contents of the `RecordBatch` with the contents of the log file to verify this.)
+
     marketing_md: |-
       In this stage, you'll implement the Fetch response for a topic with a single message, reading it from disk.
 
@@ -743,6 +803,37 @@ stages:
     name: "Fetch multiple messages from disk"
     difficulty: hard
     description_md: |-
-      🚧 **We're still working on tests for this stage!**.
+      In this stage, you'll implement the Fetch response for a topic with multiple messages, reading them from disk.
+
+      🚧 **We're still working on instructions for this stage**. You can find notes on how the tester works below.
+
+      In the meantime, please use
+      [this link](https://forum.codecrafters.io/new-topic?category=Challenges&tags=challenge%3Akafka&title=Question+about+fd8%3A+Fetch+multiple+messages+from+disk&body=%3Cyour+question+here%3E)
+      to ask questions on the forum.
+
+      ### Tests
+
+      The tester will execute your program like this:
+
+      ```bash
+      $ ./your_program.sh
+      ```
+
+      It'll then connect to your server on port 9092 and send a `Fetch` (v16) request. The request will contain a single topic with a topic ID that exists. The topic has multiple messages assigned to it (but written to a single partition).
+
+      The tester will validate that:
+
+      - The first 4 bytes of your response (the "message length") are valid.
+      - The correlation ID in the response header matches the correlation ID in the request header.
+      - The error code in the response body is `0` (No Error).
+      - The `throttle_time_ms` field in the response is present (any value is accepted).
+      - The `responses` field in the response has 1 element, and in that element:
+        - The `topic_id` field matches what was sent in the request.
+        - The `partitions` array has 1 element, and in that element:
+          - The `partition_index` field is `0`.
+          - The `error_code` field is `0` (No Error).
+          - The `records` array has the correct number of elements.
+            - The entire `RecordBatch` content is read from disk. (We will compare the contents of the `RecordBatch` with the contents of the log file to verify this.)
+
     marketing_md: |-
       In this stage, you'll implement the Fetch response for a topic with multiple messages, reading them from disk.