add one more test in example

example/exe/build.zig

@@ -67,8 +67,13 @@ pub fn build(b: *std.Build) void {
         .root_source_file = .{ .path = "src/main.zig" },
         .target = target,
         .optimize = optimize,
+        .link_libc = true,
     });
-
+    unit_tests.linkLibrary(b.dependency("zlib", .{
+        .target = target,
+        .optimize = optimize,
+    }).artifact("z"));
+    unit_tests.addModule("zlib", zlib.module("zlib"));
     const run_unit_tests = b.addRunArtifact(unit_tests);
 
     // Similar to creating the run step earlier, this exposes a `test` step to

example/exe/src/main.zig

@@ -1,5 +1,6 @@
 const std = @import("std");
 const zlib = @import("zlib");
+const testing = std.testing;
 
 pub fn main() !void {
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
@@ -27,3 +28,33 @@ test "simple test" {
     try list.append(42);
     try std.testing.expectEqual(@as(i32, 42), list.pop());
 }
+
+test "zlib compress/decompress" {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    defer _ = gpa.deinit();
+    const allocator = gpa.allocator();
+    //const allocator = testing.allocator;
+    const input = "Hello";
+
+    var cmp = try zlib.Compressor.init(allocator, .{ .header = .none });
+    defer cmp.deinit();
+
+    const compressed = try cmp.compressAllAlloc(input);
+    defer allocator.free(compressed);
+    showBuf(compressed);
+
+    var dcmp = try zlib.Decompressor.init(allocator, .{ .header = .none });
+    defer dcmp.deinit();
+
+    const decompressed = try dcmp.decompressAllAlloc(compressed);
+    defer allocator.free(decompressed);
+    try testing.expectEqualSlices(u8, input, decompressed);
+}
+
+// debug helper
+fn showBuf(buf: []const u8) void {
+    std.debug.print("\n", .{});
+    for (buf) |b|
+        std.debug.print("0x{x:0>2}, ", .{b});
+    std.debug.print("\n", .{});
+}