chore: configure kcov for test coverage

build.zig

@@ -1,6 +1,8 @@
 const std = @import("std");
 
 pub fn build(b: *std.Build) void {
+    const use_llvm = true;
+
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
     const mod = b.addModule("ink", .{
@@ -32,13 +34,29 @@ pub fn build(b: *std.Build) void {
 
     const mod_tests = b.addTest(.{
         .root_module = mod,
+        .use_llvm = use_llvm,
+        .use_lld = use_llvm,
     });
     const run_mod_tests = b.addRunArtifact(mod_tests);
+
     const exe_tests = b.addTest(.{
         .root_module = exe.root_module,
+        .use_llvm = use_llvm,
+        .use_lld = use_llvm,
     });
     const run_exe_tests = b.addRunArtifact(exe_tests);
+
     const test_step = b.step("test", "Run tests");
     test_step.dependOn(&run_mod_tests.step);
     test_step.dependOn(&run_exe_tests.step);
+
+    const run_cover = b.addSystemCommand(&.{
+        "kcov",
+        "--clean",
+        "--include-pattern=src/",
+        b.pathJoin(&.{ b.install_path, "cover" }),
+    });
+    run_cover.addArtifactArg(mod_tests);
+    const cover_step = b.step("cover", "Generate test coverage report");
+    cover_step.dependOn(&run_cover.step);
 }

src/Story/runtime_tests.zig

@@ -1,6 +1,6 @@
 const std = @import("std");
 const fatal = std.process.fatal;
-const ink = @import("root.zig");
+const ink = @import("../root.zig");
 
 const Options = struct {
     input_reader: *std.Io.Reader,

src/root.zig

@@ -6,5 +6,5 @@ test {
     _ = tokenizer;
     _ = Ast;
     _ = Story;
-    _ = @import("runtime_tests.zig");
+    _ = @import("Story/runtime_tests.zig");
 }