bring build.zig in line with zig 0.13.0

build.zig

@@ -15,15 +15,26 @@ pub fn build(b: *std.Build) void {
     // set a preferred release mode, allowing the user to decide how to optimize.
     const optimize = b.standardOptimizeOption(.{});
 
-    const exe = b.addExecutable(.{
+    const lib = b.addStaticLibrary(.{
         .name = "zetviel",
         // In this case the main source file is merely a path, however, in more
         // complicated build scripts, this could be a generated file.
-        .root_source_file = .{ .path = "src/main.zig" },
+        .root_source_file = b.path("src/root.zig"),
         .target = target,
         .optimize = optimize,
     });
 
+    // This declares intent for the library to be installed into the standard
+    // location when the user invokes the "install" step (the default step when
+    // running `zig build`).
+    b.installArtifact(lib);
+
+    const exe = b.addExecutable(.{
+        .name = "zetviel",
+        .root_source_file = b.path("src/main.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
     // This declares intent for the executable to be installed into the
     // standard location when the user invokes the "install" step (the default
     // step when running `zig build`).
@@ -54,17 +65,26 @@ pub fn build(b: *std.Build) void {
 
     // Creates a step for unit testing. This only builds the test executable
     // but does not run it.
-    const unit_tests = b.addTest(.{
+    const lib_unit_tests = b.addTest(.{
-        .root_source_file = .{ .path = "src/main.zig" },
+        .root_source_file = b.path("src/root.zig"),
         .target = target,
         .optimize = optimize,
     });
 
-    const run_unit_tests = b.addRunArtifact(unit_tests);
+    const run_lib_unit_tests = b.addRunArtifact(lib_unit_tests);
+
+    const exe_unit_tests = b.addTest(.{
+        .root_source_file = b.path("src/main.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const run_exe_unit_tests = b.addRunArtifact(exe_unit_tests);
 
     // Similar to creating the run step earlier, this exposes a `test` step to
     // the `zig build --help` menu, providing a way for the user to request
     // running the unit tests.
     const test_step = b.step("test", "Run unit tests");
-    test_step.dependOn(&run_unit_tests.step);
+    test_step.dependOn(&run_lib_unit_tests.step);
+    test_step.dependOn(&run_exe_unit_tests.step);
 }

src/root.zig

@@ -0,0 +1,10 @@
+const std = @import("std");
+const testing = std.testing;
+
+export fn add(a: i32, b: i32) i32 {
+    return a + b;
+}
+
+test "basic add functionality" {
+    try testing.expect(add(3, 7) == 10);
+}