feat(developer): test local imports in kmc-ldml

- also improve callback visibility when XML fails to load

Fixes: #10649

developer/src/kmc-ldml/test/fixtures/sections/keys/import-local.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<keyboard3 xmlns="https://schemas.unicode.org/cldr/45/keyboard3" locale="mt" conformsTo="45">
+  <info name="keys-minimal"/>
+
+  <keys>
+    <import base="" path="keys-Zyyy-morepunctuation.xml"/>
+  </keys>
+
+  <layers formId="us">
+    <layer id="base">
+      <row keys="snail interrobang" />
+    </layer>
+  </layers>
+
+</keyboard3>

developer/src/kmc-ldml/test/fixtures/sections/keys/keys-Zyyy-morepunctuation.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<keys>
+    <!-- Special Symbols -->
+    <key id="interrobang" output="‽" />
+    <key id="snail" output="@" />
+</keys>

developer/src/kmc-ldml/test/helpers/index.ts

@@ -38,7 +38,8 @@ export const compilerTestCallbacks = new TestCompilerCallbacks();
 
 export const compilerTestOptions: LdmlCompilerOptions = {
   readerOptions: {
-    importsPath: fileURLToPath(new URL(...LDMLKeyboardXMLSourceFileReader.defaultImportsURL))
+    importsPath: fileURLToPath(new URL(...LDMLKeyboardXMLSourceFileReader.defaultImportsURL)),
+    localImportsPaths: [], // will be fixed up in loadSectionFixture
   }
 };
 
@@ -59,8 +60,14 @@ export async function loadSectionFixture(compilerClass: SectionCompilerNew, file
   const data = callbacks.loadFile(inputFilename);
   assert.isNotNull(data, `Failed to read file ${inputFilename}`);
 
+  compilerTestOptions.readerOptions.localImportsPaths =  [ path.dirname(inputFilename) + path.sep ];
+
   const reader = new LDMLKeyboardXMLSourceFileReader(compilerTestOptions.readerOptions, callbacks);
   const source = reader.load(data);
+  if (!source) {
+    // print any callbacks here
+    assert.sameDeepMembers(callbacks.messages, [], `Errors loading ${inputFilename}`);
+  }
   assert.isNotNull(source, `Failed to load XML from ${inputFilename}`);
 
   if (!reader.validate(source)) {

developer/src/kmc-ldml/test/keys.tests.ts

@@ -199,6 +199,19 @@ describe('keys', function () {
         assert.equal(flickw.flicks[0].keyId.value, 'dd');
       },
     },
+    {
+      subpath: 'sections/keys/import-local.xml',
+      callback: (keys, subpath, callbacks) => {
+        assert.isNotNull(keys);
+        assert.equal((<Keys>keys).keys.length, 2 + KeysCompiler.reserved_count);
+        const [snail] = (<Keys>keys).keys.filter(({ id }) => id.value === 'snail');
+        assert.ok(snail,`Missing the snail`);
+        assert.equal(snail.to.value, `@`, `Snail's value`);
+        const [interrobang] = (<Keys>keys).keys.filter(({ id }) => id.value === 'interrobang');
+        assert.ok(interrobang,`Missing the interrobang`);
+        assert.equal(interrobang.to.value, `‽`, `Interrobang's value`);
+      },
+    },
   ], keysDependencies);
 });