From 08c9a27266df57c72f84bce3766e590c9cdc0aab Mon Sep 17 00:00:00 2001
From: Michael Peters <michael@styx>
Date: Thu, 29 Aug 2024 15:54:33 -0700
Subject: [PATCH] add tests for computeNextGeneration

---
 src/site/snake/neat.ts |  8 ++---
 src/test/test-neat.ts  | 69 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+), 6 deletions(-)

diff --git a/src/site/snake/neat.ts b/src/site/snake/neat.ts
index 7a0e9da..65a5061 100644
--- a/src/site/snake/neat.ts
+++ b/src/site/snake/neat.ts
@@ -228,7 +228,7 @@
  *   - Effectively pass data from inputs, through hidden nodes, to outputs
  */
 
-import { edgesToNodes, NodeID, Network, Node, topoSort, traceParents, RawEdge } from './network';
+import { edgesToNodes, NodeID, traceParents, RawEdge } from './network';
 import { keyMax, mapInvert, mapMap, randchoice, randint, randomNegPos, setDifference, setMap } from './util';
 
 export interface GeneData {
@@ -589,7 +589,7 @@ export function mutate(genome: Genome, config: MutateConfig): Genome {
     return newGenome;
 }
 
-interface NextGenerationConfig {
+export interface NextGenerationConfig {
     fc: FertilityConfig;
     mcc: MateChoiceConfig;
     cc: CrossConfig;
@@ -624,9 +624,5 @@ export function computeNextGeneration(
         nextGeneration.set(baby, sid);
     }
 
-    // TODO: consider adding a test for this function
-    // TODO: consider renaming the top part of this file "neat.ts" and the
-    //       bottom part (activate and below) to be in a new file "brain-neat.ts"
-
     return nextGeneration;
 }
diff --git a/src/test/test-neat.ts b/src/test/test-neat.ts
index fb0be10..f61d642 100644
--- a/src/test/test-neat.ts
+++ b/src/test/test-neat.ts
@@ -13,6 +13,8 @@ import {
     Population,
     resetGlobalIDs,
     assignSpecies,
+    NextGenerationConfig,
+    computeNextGeneration,
 } from '../site/snake/neat';
 import { assert, addTest, assertSetEqual, assertDeepEqual } from './tests';
 
@@ -405,3 +407,70 @@ function testFindAcyclicNewConns() {
     assertDeepEqual(options, expected);
 }
 addTest(testFindAcyclicNewConns);
+
+function testComputeNextGeneration() {
+    function makeGenome(weight: number) {
+        return [{ src_id: 'A', dst_id: 'B', data: { innovation: 1, weight, enabled: true } }];
+    }
+    const genomeA = makeGenome(1);
+    const genomeB = makeGenome(2);
+    const genomeC = makeGenome(3);
+    const genomeD = makeGenome(4);
+    const genomeE = makeGenome(5);
+
+    const population = new Map();
+    population.set(genomeA, 1);
+    population.set(genomeB, 1);
+    population.set(genomeC, 1);
+    population.set(genomeD, 2);
+    population.set(genomeE, 2);
+
+    const fitness = new Map();
+    fitness.set(genomeA, 1);
+    fitness.set(genomeB, 2);
+    fitness.set(genomeC, 1);
+    fitness.set(genomeD, 1);
+    fitness.set(genomeE, 2);
+
+    const cngc: NextGenerationConfig = {
+        fc: {
+            fertile_threshold: 0.6,
+            champion_min_species_size: 3,
+        },
+        mcc: {
+            asexual_rate: 0.5,
+            interspecies_rate: 0.2,
+        },
+        cc: {
+            reenable_rate: 0.25,
+        },
+        mc: {
+            mutate_rate: 0.25,
+            assign_rate: 0.1,
+            assign_mag: 1.0,
+            perturb_mag: 0.1,
+            new_node_rate: 0.2,
+            new_connection_rate: 0.1,
+        },
+        cdc: {
+            c1: 1,
+            c2: 1,
+            c3: 10,
+        },
+        cdt: 1.0,
+    };
+
+    resetGlobalIDs({ node_id: 1, innovation_number: 2, species_id: 3 });
+    const ng = computeNextGeneration(population, fitness, cngc);
+
+    // NOTE: these tests are not very detailed as this is difficult
+    //       to test without mocks
+    assert(ng.size === population.size);
+
+    const sids = new Set(ng.values());
+    assert(sids.has(1));
+    assert(!sids.has(2));
+    // it not guaranteed that sids.has(3) since the new genomes may have the
+    // same species as the species 1 champ
+}
+addTest(testComputeNextGeneration);