Correct back reference to Hello World

Author: pinin4fjords

docs/side_quests/nf-test.md

@@ -49,6 +49,66 @@ nf-test
 ```
 
 For a detailed description of the files, see the [warmup from Hello Nextflow](../hello_nextflow/00_orientation.md).
+The workflow we'll be testing is part of the workflow built in [Hello Workflow](../hello_nextflow/03_hello_workflow.md), and is composed of two processes: `sayHello` and `convertToUpper`:
+
+```bash title="Workflow code"
+/*
+ * Pipeline parameters
+ */
+params.input_file = "greetings.csv"
+
+/*
+ * Use echo to print 'Hello World!' to standard out
+ */
+process sayHello {
+
+    publishDir 'results', mode: 'copy'
+
+    input:
+        val greeting
+
+    output:
+        path "${greeting}-output.txt"
+
+    script:
+    """
+    echo '$greeting' > '$greeting-output.txt'
+    """
+}
+
+/*
+ * Use a text replace utility to convert the greeting to uppercase
+ */
+process convertToUpper {
+
+    publishDir 'results', mode: 'copy'
+
+    input:
+        path input_file
+
+    output:
+        path "UPPER-${input_file}"
+
+    script:
+    """
+    cat '$input_file' | tr '[a-z]' '[A-Z]' > UPPER-${input_file}
+    """
+}
+
+workflow {
+
+    // create a channel for inputs from a CSV file
+    greeting_ch = Channel.fromPath(params.input_file).splitCsv().flatten()
+
+    // emit a greeting
+    sayHello(greeting_ch)
+
+    // convert the greeting to uppercase
+    convertToUpper(sayHello.out)
+}
+```
+
+We're going to assume an understanding of this workflow, but if you're not sure, you can refer back to [Hello Workflow](../hello_nextflow/03_hello_workflow.md).
 
 ### 0.1. Run the workflow
 
@@ -613,7 +673,7 @@ Test Process sayHello
 FAILURE: Executed 1 tests in 4.884s (1 failed)
 ```
 
-The test fails because the `sayHello` process declares 1 input channel but 0 were specified. Let's fix that by adding an input to the process. Remember from part 1, our `sayHello` process takes a single value input. We should also fix the test name to better reflect what we're testing.
+The test fails because the `sayHello` process declares 1 input channel but 0 were specified. Let's fix that by adding an input to the process. Remember from [Hello Workflow](../hello_nextflow/03_hello_workflow.md) (and the warmup section above) that our `sayHello` process takes a single value input, which we will need to provide. We should also fix the test name to better reflect what we're testing.
 
 **Before:**