solution for pub struct TestIndividual

[alexxroche]

L710 pub struct TestIndividual and then TestIndividual evolves into L2381 pub enum TestIndividual without ensuring that the previous section still passes for i in fmt check test;do cargo $i; done

[Patryk27]

How about this one instead?

diff --git a/src/content/en/posts/learning-to-fly-pt3.adoc b/src/content/en/posts/learning-to-fly-pt3.adoc
index caca364..e809fc7 100644
--- a/src/content/en/posts/learning-to-fly-pt3.adoc
+++ b/src/content/en/posts/learning-to-fly-pt3.adoc
@@ -2227,6 +2227,15 @@ pub trait Individual {

     /* ... */
 }
+
+/* ... */
+
+#[cfg(test)]
+impl Individual for TestIndividual {
+    fn create(chromosome: Chromosome) -> Self {
+       todo!()
+    }
+}
 ----

 [NOTE]

All tests up to that point don't use Individual::create() (so todo!() won't hurt) + we're implementing proper ::create() in the very next section (so there's no need to use chromosome.genes[0], which will get replaced in a moment anyway)

[alexxroche]

That might work. It wasn't clear that pub enum TestIndividual was replacing pub struct TestIndividual or why it wasn't an enum in the first place? Discovering a need to change to a difference data object in the middle of development is common, but there is always a reason. It felt like you went from {A..F} and I'm wondering where B,C,D,E are? (Which might say more about my inability to keep up with your brilliant mind.)

[Patryk27]

It felt like you went from {A..F} and I'm wondering where B,C,D,E are?

Fair point - what do you think of this one?

commit 40e4584cfdd449efea8f18590e73f1ff4d83c961
Author: Patryk Wychowaniec <wychowaniec.patryk@gmail.com>
Date:   Thu Apr 8 16:44:38 2021 +0200

    posts(learning-to-fly-pt3): Highlight changing TestIndividual to enum

diff --git a/src/content/en/posts/learning-to-fly-pt3.adoc b/src/content/en/posts/learning-to-fly-pt3.adoc
index caca364..909ec74 100644
--- a/src/content/en/posts/learning-to-fly-pt3.adoc
+++ b/src/content/en/posts/learning-to-fly-pt3.adoc
@@ -2227,6 +2227,15 @@ pub trait Individual {

     /* ... */
 }
+
+/* ... */
+
+#[cfg(test)]
+impl Individual for TestIndividual {
+    fn create(chromosome: Chromosome) -> Self {
+       todo!()
+    }
+}
 ----

 [NOTE]
@@ -2353,14 +2362,17 @@ We'll start by adjusting our `TestIndividual` so that instead of `panic!()`-ing,

 Some tests - e.g. the ones for `RouletteWheelSelection` - don't care about genes at all, so we'll get bonus points for inventing a solution that doesn't require modifying those already-working tests.

-My proposition is:
+My proposition is to change `TestIndividual` from `struct` to an `enum` with two different variants:

 [source, rust]
 ----
 #[cfg(test)]
 #[derive(Clone, Debug, PartialEq)]
 pub enum TestIndividual {
+    /// For tests that require access to chromosome
     WithChromosome { chromosome: Chromosome },
+
+    /// For tests that don't require access to chromosome
     WithFitness { fitness: f32 },
 }

(You can see it deployed at https://pwy.io/en/posts/learning-to-fly-pt3/.)

Which might say more about my inability to keep up with your brilliant mind.

No such thing! All unclear explanations are on me - no need to self-deprecate 🙂

[alexxroche]

Looks, to me, like you have created a perfect patch.