test: fix crate dependency suggestion

Fixes #377

src/command/test.rs

@@ -273,7 +273,7 @@ impl Test {
                 "Ensure that you have \"{}\" as a dependency in your Cargo.toml file:\n\
                  [dev-dependencies]\n\
                  wasm-bindgen-test = \"0.2\"",
-                style("wasm-bindgen").bold().dim(),
+                style("wasm-bindgen-test").bold().dim(),
             );
             return Err(Error::CrateConfig { message });
         }

tests/all/test.rs

@@ -176,3 +176,76 @@ fn the_headless_flag_requires_a_browser() {
         "running headless tests in node doesn't make sense"
     );
 }
+
+#[test]
+fn complains_about_missing_wasm_bindgen_test_dependency() {
+    let fixture = fixture::Fixture::new();
+    fixture
+        .readme()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                authors = ["The wasm-pack developers"]
+                description = "so awesome rust+wasm package"
+                license = "WTFPL"
+                name = "missing-wbg-test"
+                repository = "https://github.com/rustwasm/wasm-pack.git"
+                version = "0.1.0"
+
+                [lib]
+                crate-type = ["cdylib"]
+
+                [dependencies]
+                wasm-bindgen = "=0.2.21"
+
+                [dev-dependencies]
+                # no wasm-bindgen-test dep here!
+            "#,
+        ).hello_world_src_lib()
+        .install_local_wasm_bindgen();
+
+    let cmd = Command::Test(test::TestOptions {
+        path: Some(fixture.path.clone()),
+        node: true,
+        mode: build::BuildMode::Noinstall,
+        ..Default::default()
+    });
+    let logger = logger::new(&cmd, 3).unwrap();
+
+    let result = command::run_wasm_pack(cmd, &logger);
+    assert!(
+        result.is_err(),
+        "running tests without wasm-bindgen-test won't work"
+    );
+
+    // Test that the error message has two occurrences of "wasm-bindgen-test" in
+    // it. I am surprised to learn there is no `str` method to count
+    // occurrences, so we find the first and the last and assert that they
+    // aren't the same occurrence.
+    //
+    // This should protect against regresstions where we said:
+    //
+    //     Ensure that you have "wasm-bindgen" as a dependency in your Cargo.toml file:
+    //     [dev-dependencies]
+    //     wasm-bindgen-test = "0.2"
+    //
+    // instead of
+    //
+    //     Ensure that you have "wasm-bindgen-test" as a dependency in your Cargo.toml file:
+    //     [dev-dependencies]
+    //     wasm-bindgen-test = "0.2"
+    //
+    // Note that the whole reason we are doing this string manipulation instead
+    // of just doing `assert_eq!` is because the first occurrence of the
+    // dependency name is bolded with terminal escape codes and if I try to pipe
+    // the output to a text file, then the escape codes go away, so I can't
+    // figure out which exact escape codes are even used here.
+
+    let err_msg = result.unwrap_err().to_string();
+    let first = err_msg.find("wasm-bindgen-test");
+    assert!(first.is_some());
+    let second = err_msg.rfind("wasm-bindgen-test");
+    assert!(second.is_some());
+    assert_ne!(first, second, "should have found two occurrences");
+}