test: add prerelease version comparison edge case tests

The comparePrerelease function handles numeric vs string identifiers,
length differences, and mixed types, but only one basic prerelease
test existed. Add coverage for numeric comparison, string ordering,
numeric-before-string precedence, length comparison, and equal
prerelease identity.

Signed-off-by: Sebastien Tardif <sebtardif@ncf.ca>

Author: SebTardif

test/unit/binaryDiscovery.test.ts

@@ -147,6 +147,27 @@ test("comparePatchloomVersions handles major, minor, and patch differences", ()
   assert.equal(comparePatchloomVersions("1.2.3", "1.2.3"), 0);
 });
 
+test("comparePatchloomVersions compares prerelease identifiers correctly", () => {
+  // Two prereleases: numeric comparison
+  assert.ok(comparePatchloomVersions("0.1.0-alpha.1", "0.1.0-alpha.2") < 0);
+  assert.ok(comparePatchloomVersions("0.1.0-alpha.10", "0.1.0-alpha.2") > 0);
+
+  // Two prereleases: string comparison
+  assert.ok(comparePatchloomVersions("0.1.0-alpha", "0.1.0-beta") < 0);
+
+  // Numeric identifier < string identifier
+  assert.ok(comparePatchloomVersions("0.1.0-1", "0.1.0-alpha") < 0);
+
+  // Shorter prerelease < longer prerelease when prefix matches
+  assert.ok(comparePatchloomVersions("0.1.0-alpha", "0.1.0-alpha.1") < 0);
+
+  // Both prereleases equal
+  assert.equal(comparePatchloomVersions("0.1.0-beta.1", "0.1.0-beta.1"), 0);
+
+  // Release > prerelease
+  assert.ok(comparePatchloomVersions("0.1.0", "0.1.0-rc.1") > 0);
+});
+
 test("assessPatchloomCompatibility correctly identifies supported versions", () => {
   const supported = assessPatchloomCompatibility("patchloom 0.1.0");
   assert.equal(supported.compatibility, "supported");