fix: don't post contents of unknown commands to chat (#6272)

tests/src/TwitchChannel.cpp

@@ -0,0 +1,53 @@
+#include "providers/twitch/TwitchChannel.hpp"
+
+#include "Test.hpp"
+
+#include <QString>
+
+#include <vector>
+
+namespace chatterino::detail {
+
+TEST(TwitchChannelDetail_isUnknownCommand, good)
+{
+    // clang-format off
+    std::vector<QString> cases{
+        "/me hello",
+        ".me hello",
+        "/ hello",
+        ". hello",
+        "/ /hello",
+        ". .hello",
+        "/ .hello",
+        ". /hello",
+    };
+    // clang-format on
+
+    for (const auto &input : cases)
+    {
+        ASSERT_FALSE(isUnknownCommand(input))
+            << input << " should not be considered an unknown command";
+    }
+}
+
+TEST(TwitchChannelDetail_isUnknownCommand, bad)
+{
+    // clang-format off
+    std::vector<QString> cases{
+        "/badcommand",
+        ".badcommand",
+        "/badcommand hello",
+        ".badcommand hello",
+        "/@badcommand hello",
+        ".@badcommand hello",
+    };
+    // clang-format on
+
+    for (const auto &input : cases)
+    {
+        ASSERT_TRUE(isUnknownCommand(input))
+            << input << " should be considered an unknown command";
+    }
+}
+
+}  // namespace chatterino::detail