[LL API] Add tests for 'FileBasedKotlinDeclarationProvider'

analysis/low-level-api-fir/testdata/fileBasedDeclarationProvider/defaultPackage.kt

@@ -0,0 +1,9 @@
+// CLASS: Foo
+// CLASS: Foo.Bar
+// FUNCTION: /#foo
+
+class Foo {
+    object Bar
+}
+
+fun foo() {}

analysis/low-level-api-fir/testdata/fileBasedDeclarationProvider/local.kt

@@ -0,0 +1,12 @@
+// FUNCTION: test/#foo
+
+package test
+
+fun foo() {
+    fun bar() {
+        fun baz() {
+            class Foo
+            object Bar
+        }
+    }
+}

analysis/low-level-api-fir/testdata/fileBasedDeclarationProvider/sameNames.kt

@@ -0,0 +1,29 @@
+// CLASS: test/Foo
+// CLASS: test/Bar
+// CLASS: test/Bar.Baz
+// CLASS: test/Bar.Boo
+// CLASS: test/Bar.Bok
+// FUNCTION: test/#foo
+// PROPERTY: test/#foo
+
+package test
+
+class Foo
+interface Foo
+typealias Foo = Foo
+enum class Foo
+
+class Bar {
+    class Baz
+    object Boo
+}
+
+interface Bar {
+    object Baz
+    interface Bok
+}
+
+fun foo() {}
+fun foo(a: Int) {}
+
+val foo: String = "foo"

analysis/low-level-api-fir/testdata/fileBasedDeclarationProvider/simple.kt

@@ -0,0 +1,22 @@
+// CLASS: test/app/Foo
+// CLASS: test/app/Foo.Bar
+// CLASS: test/app/Foo.Bar.Baz
+// TYPE_ALIAS: test/app/MyString
+// FUNCTION: test/app/#foo
+// PROPERTY: test/app/#bar
+
+package test.app
+
+interface Foo {
+    class Bar {
+        object Baz
+    }
+
+    fun nested() {}
+}
+
+typealias MyString = String
+
+fun foo() {}
+
+val bar: String = "bar"