Implement a repl characterization test system

This allows for automating using the repl without needing a PTY, with
very easy to write test files.

Change-Id: Ia8d7854edd91f93477638942cb6fc261354e6035

1 files changed, 58 insertions, 0 deletions

diff --git a/tests/functional/repl_characterization/repl_characterization.cc b/tests/functional/repl_characterization/repl_characterization.cc
index 5b73e7a89..993c30232 100644
--- a/tests/functional/repl_characterization/repl_characterization.cc
+++ b/tests/functional/repl_characterization/repl_characterization.cc
@@ -5,8 +5,11 @@
 #include <optional>
 #include <unistd.h>
 
+#include "test-session.hh"
+#include "util.hh"
 #include "tests/characterization.hh"
 #include "tests/cli-literate-parser.hh"
+#include "tests/terminal-code-eater.hh"
 
 using namespace std::string_literals;
 
@@ -14,6 +17,18 @@ namespace nix {
 
 static constexpr const char * REPL_PROMPT = "nix-repl> ";
 
+// ASCII ENQ character
+static constexpr const char * AUTOMATION_PROMPT = "\x05";
+
+static std::string_view trimOutLog(std::string_view outLog)
+{
+    const std::string trailer = "\n"s + AUTOMATION_PROMPT;
+    if (outLog.ends_with(trailer)) {
+        outLog.remove_suffix(trailer.length());
+    }
+    return outLog;
+}
+
 class ReplSessionTest : public CharacterizationTest
 {
     Path unitTestData = getUnitTestData();
@@ -23,6 +38,43 @@ public:
     {
         return unitTestData + "/" + testStem;
     }
+
+    void runReplTest(std::string_view const & content, std::vector<std::string> extraArgs = {}) const
+    {
+        auto syntax = CLILiterateParser::parse(REPL_PROMPT, content);
+
+        // FIXME: why does this need two --quiets
+        // show-trace is on by default due to test configuration, but is not a standard
+        Strings args{"--quiet", "repl", "--quiet", "--option", "show-trace", "false", "--offline", "--extra-experimental-features", "repl-automation"};
+        args.insert(args.end(), extraArgs.begin(), extraArgs.end());
+
+        auto nixBin = canonPath(getEnvNonEmpty("NIX_BIN_DIR").value_or(NIX_BIN_DIR));
+
+        auto process = RunningProcess::start(nixBin + "/nix", args);
+        auto session = TestSession{AUTOMATION_PROMPT, std::move(process)};
+
+        for (auto & bit : syntax) {
+            if (bit.kind != CLILiterateParser::NodeKind::COMMAND) {
+                continue;
+            }
+
+            if (!session.waitForPrompt()) {
+                ASSERT_TRUE(false);
+            }
+            session.runCommand(bit.text);
+        }
+        if (!session.waitForPrompt()) {
+            ASSERT_TRUE(false);
+        }
+        session.close();
+
+        auto parsedOutLog = CLILiterateParser::parse(AUTOMATION_PROMPT, trimOutLog(session.outLog), 0);
+
+        parsedOutLog = CLILiterateParser::tidyOutputForComparison(std::move(parsedOutLog));
+        syntax = CLILiterateParser::tidyOutputForComparison(std::move(syntax));
+
+        ASSERT_EQ(parsedOutLog, syntax);
+    }
 };
 
 TEST_F(ReplSessionTest, parses)
@@ -39,4 +91,10 @@ TEST_F(ReplSessionTest, parses)
         return out.str();
     });
 }
+
+TEST_F(ReplSessionTest, repl_basic)
+{
+    readTest("basic_repl.test", [this](std::string input) { runReplTest(input); });
+}
+
 };