ICU-22927 Duplicate (back) the MF2 test data between icu4c and icu4j

The C++ and Java implementations are done by two different people different companies.
With different time constraints and availability.
The spec is still not final (although it is close), and the implementations are
still quite a bit behind.
Sharing these test files slows down development, by forcing any C++ and Java changes
to happen in the same time.

There are other components that share test files that are not shared yet,
even if they are more stable. So I don't know why we would force this on MF2 only.

This is temporary, and the data files will be de-duplicated again at a later time,
when the two implementations are more stable.
That de-duplication will include other shared files, and in a slightly different structure
(we have a doc and a discution on this topic).

icu4j/main/core/src/test/java/com/ibm/icu/dev/test/message2/TestUtils.java

@@ -200,20 +200,5 @@ private static Path getTestFile(Class<?> cls, String fileName) throws URISyntaxE
         URI getPath = cls.getClassLoader().getResource(packageName).toURI();
         Path filePath = Paths.get(getPath);
         Path json = Paths.get(fileName);
-        // First, check the top level of the source directory,
-        // in case we're in a source tarball
-        Path icuTestdataInSourceDir = filePath.resolve("../../../../../../../../../../../testdata/message2/").normalize();
-        Path icuTestdataDir = icuTestdataInSourceDir;
-        if (!Files.isDirectory(icuTestdataInSourceDir)) {
-            // If that doesn't exist, check one directory higher, in case we're
-            // in a checked-out repo
-            Path icuTestdataInRepo = Paths.get("../").resolve(icuTestdataInSourceDir).normalize();
-            if (!Files.isDirectory(icuTestdataInRepo)) {
-                throw new java.io.FileNotFoundException("Test data directory does not exist: tried "
-                                                        + icuTestdataInSourceDir + " and "
-                                                        + icuTestdataInRepo);
-            }
-            icuTestdataDir = icuTestdataInSourceDir;
-        }
-        return icuTestdataDir.resolve(json);
+        return filePath.resolve(json);
     }}

icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/message2/README.txt

@@ -0,0 +1,43 @@
+© 2024 and later: Unicode, Inc. and others.
+License & terms of use: http://www.unicode.org/copyright.html
+
+The format of the JSON files in this directory and subdirectories
+follow the test schema defined in the Conformance repository:
+
+https://github.com/unicode-org/conformance/blob/main/schema/message_fmt2/testgen_schema.json
+
+(as of https://github.com/unicode-org/conformance/pull/255 or later).
+
+# JSON notes
+
+In the "params" field, a date parameter can be expressed as:
+{ "date": n }
+where n is a number representing a Unix timestamp.
+
+In the "params" field, a decimal string parameter can be expressed as:
+{ "decimal": s }
+where s is a string.
+
+Optional fields, "ignoreJava" and "ignoreCpp" can be used
+for tests currently expected to fail in the respective language.
+The field may have any value; if it's
+present, the test is ignored. (The value can be a comment explaining
+why it's expected to fail.)
+
+Tests in the `spec/` subdirectory are taken from https://github.com/unicode-org/message-format-wg/blob/main/test .
+If the contents change upstream, then the corresponding tests in CLDR
+need to be updated (also see https://unicode-org.atlassian.net/browse/ICU-22812 ).
+
+## ICU4J only
+
+The `cleanSrc` fields is used to represent normalized input (ICU4C has its
+own function for normalizing input).
+
+## ICU4C only
+
+Additional "char" and "line" fields may be present with integer values,
+used for tests expected to trigger a syntax error.
+If present, "char" reflects the expected character offset and "line"
+reflects the expected line number in the parse error.
+The files with "diagnostics" in the name have these fields filled in.
+

icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/message2/alias-selector-annotations.json

@@ -0,0 +1,18 @@
+{
+  "scenario": "Selector annotations",
+  "description": "Tests for indirectly annotated selectors",
+  "defaultTestProperties": {
+    "locale": "en-US"
+  },
+  "tests": [
+    {
+        "src": ".local $one = {|The one| :string}\n   .match {$one}\n   1 {{Value is one}}\n  * {{Value is not one}}",
+        "exp": "Value is not one"
+    },
+    {
+        "src": ".local $one = {|The one| :string}\n  .local $two = {$one}\n  .match {$two}\n  1 {{Value is one}}\n   * {{Value is not one}}",
+        "exp": "Value is not one"
+    }
+  ]
+}
+

icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/message2/duplicate-declarations.json

@@ -0,0 +1,43 @@
+{
+  "scenario": "Duplicate declaration errors",
+  "description": "Tests that should trigger a duplicate declaration error",
+  "defaultTestProperties": {
+    "locale": "en-US",
+    "expErrors": [
+      {
+        "type": "duplicate-declaration"
+      }
+    ]
+  },
+  "tests": [
+    {
+        "src": ".local $foo = {$foo} .local $foo = {42} {{bar {$foo}}}",
+        "params": [{ "name": "foo", "value": "foo" }],
+        "exp": "bar 42"
+    },
+    {
+        "src": ".local $foo = {42} .local $foo = {42} {{bar {$foo}}}",
+        "params": [{ "name": "foo", "value": "foo" }],
+        "exp": "bar 42"
+    },
+    {
+        "src": ".local $foo = {:unknown} .local $foo = {42} {{bar {$foo}}}",
+        "params": [{ "name": "foo", "value": "foo" }],
+        "exp": "bar 42"
+    },
+    {
+        "src": ".local $x = {42} .local $y = {$x} .local $x = {13} {{{$x} {$y}}}",
+        "exp": "13 42"
+    },
+    {
+        "src": ".local $foo = {$foo} {{bar {$foo}}}",
+        "params": [{ "name": "foo", "value": "foo" }],
+        "exp": "bar foo"
+    },
+    {
+        "src": ".local $foo = {$bar} .local $bar = {$baz} {{bar {$foo}}}",
+        "params": [{ "name": "baz", "value": "foo" }],
+        "exp": "bar {$bar}"
+    }
+  ]
+}

icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/message2/icu-parser-tests.json

@@ -0,0 +1,57 @@
+{
+  "scenario": "Valid tests",
+  "description": "Additional valid tests",
+  "defaultTestProperties": {
+    "locale": "en-US"
+  },
+  "tests": [
+    { "src": "" },
+    { "src": "Hello" },
+    { "src": "Hello world!" },
+    { "src": "Hello \t \n \r \\{ world!" },
+    { "src": "Hello world {:datetime}" },
+    { "src": "Hello world {foo}" },
+    { "src": "Hello {0} world" },
+    { "src": "Hello {123} world" },
+    { "src": "Hello {-123} world" },
+    { "src": "Hello {3.1416} world" },
+    { "src": "Hello {-3.1416} world" },
+    { "src": "Hello {123E+2} world" },
+    { "src": "Hello {123E-2} world" },
+    { "src": "Hello {123.456E+2} world" },
+    { "src": "Hello {123.456E-2} world" },
+    { "src": "Hello {-123.456E+2} world" },
+    { "src": "Hello {-123.456E-2} world" },
+    { "src": "Hello {-123E+2} world" },
+    { "src": "Hello {-123E-2} world" },
+    { "src": "Hello world {$exp}" },
+    { "src": "Hello world {$exp :datetime}" },
+    { "src": "Hello world {|2024-02-27| :datetime}" },
+    { "src": "Hello world {$exp :datetime style=long} and more" },
+    { "src": "Hello world {$exp :function number=1234} and more" },
+    { "src": "Hello world {$exp :function unquoted=left   } and more" },
+    { "src": "Hello world {$exp :function quoted=|Something| } and more" },
+    { "src": "Hello world {$exp :function quoted=|Something with spaces| } and more" },
+    { "src": "Hello world {$exp :function quoted=|Something with \\| spaces and \\| escapes| } and more" },
+    { "src": "Hello world {$exp :function number=1234 unquoted=left quoted=|Something|}" },
+    { "src": "Hello world {$exp :function number=1234 unquoted=left quoted=|Something longer|}" },
+    { "src": "Hello world {$exp :function number=1234 unquoted=left quoted=|Something \\| longer|}" },
+    { "src": "Hello world {$exp}" },
+    { "src": "Hello world {$exp @attr}" },
+    { "src": "Hello world {$exp @valid @attr=a @attrb=123 @atrn=|foo bar|}" },
+    { "src": "Hello world {$exp :date @valid @attr=aaaa @attrb=123 @atrn=|foo bar|}" },
+    { "src": "Hello world {$exp :date year=numeric month=long day=numeric int=12 @valid @attr=a @attrb=123 @atrn=|foo bar|}" },
+    { "src": "{{.starting with dot is OK here}}" },
+    { "src": "{{Some string pattern \\}, with {$foo} and {$exp :date style=long}!}}" },
+    { "src": ".input {$pi :number} {{}}" },
+    { "src": ".input {$exp :date} {{}}" },
+    { "src": ".local $foo = {$exp} {{}}" },
+    { "src": ".local $foo = {$exp :date} {{}}" },
+    { "src": ".local $foo = {$exp :date year=numeric month=long day=numeric} {{}}" },
+    { "src": ".local $bar = {$foo :date month=medium} {{}}" },
+    { "src": ".input {$a :date} .local $exp = {$a :date style=full} {{Your card expires on {$exp}!}}" },
+    { "src": ".input {$a :date} .local $b = {$a :date year=numeric month=long day=numeric} .local $c = {$b :date month=medium} {{}}" },
+    { "src": ".input {$x :number} {{_}}" },
+    { "src": ".local $foo = {|1|} {{_}}" }
+  ]
+}