Add unit testing, stabilize the container and image listing

tests/test_http_response_parser.cpp

@@ -0,0 +1,43 @@
+#include "http_response_parser.hpp"
+
+#include <cassert>
+#include <iostream>
+
+void testContentLength() {
+    const auto response = parseHttpResponse(
+        "HTTP/1.1 200 OK\r\nContent-Length: 6\r\n\r\n[1,2]\n");
+    if (!response.ok()) std::cerr << response.error << " status=" << response.status_code << " body=" << response.body << "\n";
+    assert(response.ok());
+    assert(response.body == "[1,2]\n");
+}
+
+void testChunked() {
+    const auto response = parseHttpResponse(
+        "HTTP/1.1 200 OK\r\nTransfer-Encoding: chunked\r\n\r\n"
+        "5\r\nhello\r\n6\r\n world\r\n0\r\n\r\n");
+    assert(response.ok());
+    assert(response.body == "hello world");
+}
+
+void testTruncatedBody() {
+    const auto response = parseHttpResponse(
+        "HTTP/1.1 200 OK\r\nContent-Length: 10\r\n\r\nshort");
+    assert(!response.ok());
+    assert(response.error == "Truncated HTTP response body.");
+}
+
+void testErrorResponse() {
+    const auto response = parseHttpResponse(
+        "HTTP/1.1 500 Internal Server Error\r\nContent-Length: 3\r\n\r\nbad");
+    assert(!response.ok());
+    assert(response.status_code == 500);
+    assert(response.error == "bad");
+}
+
+int main() {
+    testContentLength();
+    testChunked();
+    testTruncatedBody();
+    testErrorResponse();
+    std::cout << "HTTP response parser tests passed\n";
+}