Ignore "@instance..." part of username when computing status length (#3392)

* Move compose.* tests to own namespace

* Ignore "@instance..." part of username when computing status length

In a status with a mention ("@foo@example.org") only the "@foo" part should
be included in the calculated status length. It wasn't, so the app was
prevening people from posting statuses that should have been allowed.

Fix this.

- Lift the length calculation code in to a separate static function (easier
  and faster to test)
- Add a `MentionSpan` type, to reuse existing code for detecting mentions
- Fix a bug in `FakeSpannable.getSpans()` (it was returning the outer type,
  not the wrapped inner span)
- Add additional fast tests

The tests made sense under the `components.compose.ComposeActivity` package,
so I also created that and moved the existing ComposeActivity tests there.

Fixes https://github.com/tuskyapp/Tusky/issues/3339

* Static import assertEquals

app/src/test/java/com/keylesspalace/tusky/SpanUtilsTest.kt

@@ -136,7 +136,7 @@ class SpanUtilsTest {
         }
 
         override fun <T : Any> getSpans(start: Int, end: Int, type: Class<T>): Array<T> {
-            return spans.filter { it.start >= start && it.end <= end && type.isInstance(it) }
+            return spans.filter { it.start >= start && it.end <= end && type.isInstance(it.span) }
                 .map { it.span }
                 .toTypedArray() as Array<T>
         }

app/src/test/java/com/keylesspalace/tusky/components/compose/ComposeActivity/ComposeActivityTest.kt

@@ -1,4 +1,5 @@
-/* Copyright 2018 charlag
+/*
+ * Copyright 2018 Tusky Contributors
  *
  * This file is a part of Tusky.
  *
@@ -11,15 +12,17 @@
  * Public License for more details.
  *
  * You should have received a copy of the GNU General Public License along with Tusky; if not,
- * see <http://www.gnu.org/licenses>. */
+ * see <http://www.gnu.org/licenses>.
+ */
 
-package com.keylesspalace.tusky
+package com.keylesspalace.tusky.components.compose.ComposeActivity
 
 import android.content.Intent
 import android.os.Looper.getMainLooper
 import android.widget.EditText
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import at.connyduck.calladapter.networkresult.NetworkResult
+import com.keylesspalace.tusky.R
 import com.keylesspalace.tusky.components.compose.ComposeActivity
 import com.keylesspalace.tusky.components.compose.ComposeViewModel
 import com.keylesspalace.tusky.components.instanceinfo.InstanceInfoRepository

app/src/test/java/com/keylesspalace/tusky/components/compose/ComposeActivity/StatusLengthTest.kt

@@ -0,0 +1,79 @@
+/*
+ * Copyright 2023 Tusky Contributors
+ *
+ * This file is a part of Tusky.
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Tusky; if not,
+ * see <http://www.gnu.org/licenses>.
+ */
+
+package com.keylesspalace.tusky.components.compose.ComposeActivity
+
+import com.keylesspalace.tusky.SpanUtilsTest
+import com.keylesspalace.tusky.components.compose.ComposeActivity
+import com.keylesspalace.tusky.util.highlightSpans
+import org.junit.Assert.assertEquals
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.Parameterized
+
+@RunWith(Parameterized::class)
+class StatusLengthTest(
+    private val text: String,
+    private val expectedLength: Int
+) {
+    companion object {
+        @Parameterized.Parameters(name = "{0}")
+        @JvmStatic
+        fun data(): Iterable<Any> {
+            return listOf(
+                arrayOf("", 0),
+                arrayOf(" ", 1),
+                arrayOf("123", 3),
+                // "@user@server" should be treated as "@user"
+                arrayOf("123 @example@example.org", 12),
+                // URLs under 23 chars are treated as 23 chars
+                arrayOf("123 http://example.url", 27),
+                // URLs over 23 chars are treated as 23 chars
+                arrayOf("123 http://urlthatislongerthan23characters.example.org", 27),
+                // Short hashtags are treated as is
+                arrayOf("123 #basictag", 13),
+                // Long hashtags are *also* treated as is (not treated as 23, like URLs)
+                arrayOf("123 #atagthatislongerthan23characters", 37)
+            )
+        }
+    }
+
+    @Test
+    fun statusLength_matchesExpectations() {
+        val spannedText = SpanUtilsTest.FakeSpannable(text)
+        highlightSpans(spannedText, 0)
+
+        assertEquals(
+            expectedLength,
+            ComposeActivity.statusLength(spannedText, null, 23)
+        )
+    }
+
+    @Test
+    fun statusLength_withCwText_matchesExpectations() {
+        val spannedText = SpanUtilsTest.FakeSpannable(text)
+        highlightSpans(spannedText, 0)
+
+        val cwText = SpanUtilsTest.FakeSpannable(
+            "a @example@example.org #hashtagmention and http://example.org URL"
+        )
+        assertEquals(
+            expectedLength + cwText.length,
+            ComposeActivity.statusLength(spannedText, cwText, 23)
+        )
+    }
+}

app/src/test/java/com/keylesspalace/tusky/components/compose/ComposeTokenizer/ComposeTokenizerTest.kt

@@ -13,7 +13,7 @@
  * You should have received a copy of the GNU General Public License along with Tusky; if not,
  * see <http://www.gnu.org/licenses>. */
 
-package com.keylesspalace.tusky
+package com.keylesspalace.tusky.components.compose.ComposeTokenizer
 
 import com.keylesspalace.tusky.components.compose.ComposeTokenizer
 import org.junit.Assert