Diagnostics

Bobcat checks your specifications while they compile. The source generator in Bobcat.Generators reports BOBCATnnn diagnostics to the compiler, so they appear in the build output, in the IDE's error list and as squiggles under the code they are about. One more, BOBCAT033, is an MSBuild warning from the same package. They catch the mistakes that would otherwise show up only as a spec that silently records nothing, a stale table column, or a hole in the Event Model.

An error stops the build. A warning and an info don't. Turn a warning into an error in CI the usual way:

<WarningsAsErrors>$(WarningsAsErrors);BOBCAT027;BOBCAT028</WarningsAsErrors>

Id	Severity	Meaning
BOBCAT023	error	SliceName and SliceType name different slices
BOBCAT024	warning	A literal SliceName names a type: use SliceType
BOBCAT027	warning	A step template placeholder names no parameter
BOBCAT028	warning	A class binds a slice but nothing opens a recording
BOBCAT029	info	An And/But comment was read as prose, not a step
BOBCAT032	error	A table column or member path names no member of its type
BOBCAT033	warning (MSBuild)	An xUnit v3 project has no Microsoft.NET.Test.Sdk
BOBCAT034	error	An Event Model role or trigger names no parameter of its method
BOBCAT036	error	Two specifications share one spec identity
BOBCAT037	error	Bobcat's interceptors aren't enabled in the project
BOBCAT038	info	An HTTP act's route can't be known at compile time
BOBCAT039	error	A step helper isn't accessible to the interceptor
BOBCAT040	error	An override of an inherited [BobcatSpec] carries another test attribute
BOBCAT041	info	A specification reaches no Event Model slice
BOBCAT042	error	A [BobcatExamples] table doesn't fit its theory
BOBCAT043	warning	A Task-returning step is called and never awaited
BOBCAT044	error	A member check is not one assertion on one member
BOBCAT045	info	A specification's act goes through a helper that declares no Event Model role

Ids that are not listed were retired.

BOBCAT023 — SliceName and SliceType name different slices

Error. SliceName = "X" and SliceType = typeof(Y) name different slices. SliceType means exactly SliceName = type.Name — set one of them.

When: a [BobcatSlice] or [BobcatSpec] sets both spellings of the slice and they disagree. This holds across the two attributes too: a method carrying both is one binding stated twice.

Why: one of the two is wrong, and picking a silent winner would make the other slice vanish without a word. Setting both to the same slice is redundant but allowed.

Fix: keep one. Prefer SliceType:

[BobcatSpec(typeof(ConfirmAppointment))]   // not SliceName = "ConfirmAppointment" as well
public async Task confirming_an_open_slot() { /* … */ }

See Two spellings, and why SliceType is preferred.

BOBCAT024 — prefer SliceType over a literal SliceName

Warning. [BobcatSpec(SliceName = "X")] names a slice that IS a type in this compilation. Prefer SliceType = typeof(X): …

When: SliceName is a string literal and a type with exactly that name exists in the compilation.

Why: a type is rename-safe and survives to the generator, where a string can't be checked against the model.

Fix: [BobcatSpec(typeof(X))] or SliceType = typeof(X). Where no type bears the slice's name (an Automation slice usually has none) there is no warning, and SliceName is the right spelling.

BOBCAT027 — step template names no parameter

Warning. Step attribute on 'M' has the placeholder '{p}', but the method has no parameter named 'p' (it takes a, b). Nothing can fill it, so the step renders as '{p}'.

When: a [Given]/[When]/[Then]/[Check]/[Step]/[BobcatStep] expression contains a {placeholder} that matches no parameter of the method. Reported once per helper and placeholder, not once per call.

Why: a placeholder binds by parameter name only. Cucumber-style type captures ({int}, {word}) left with Gherkin and land here too.

Fix: rename the placeholder (or the parameter) so they match:

[When("the customer orders {quantity} widgets")]
public void Order(int quantity) { /* … */ }

See A placeholder binds from the value, not from the syntax.

BOBCAT028 — a slice is bound but nothing records

Warning. 'C' binds a slice with [BobcatSlice] but nothing opens a scenario, so none of its steps are recorded and it reaches the Event Model as no specification at all. …

When: a [BobcatFeature] class binds a slice (on the class or a method) but nothing opens a recording: no [BobcatScenario] on the class, no [BobcatSpec]/[BobcatTheory]/[BobcatScenario] on its methods, and no [assembly: Bobcat.Xunit.RecordBobcatFeatures] hook (the Bobcat.Xunit package applies that for you).

Why: without an open recording every step records into nothing and the suite passes having produced no specification. Nothing at run time can tell that apart from a suite with nothing to record, so the compiler is the only place to catch it.

Fix: add the runner's [BobcatScenario] to the class (Bobcat.Xunit, Bobcat.TUnit, Bobcat.NUnit or Bobcat.MSTest), or on xUnit replace [Fact] + [BobcatSlice] with one [BobcatSpec(typeof(TheSlice))] per test, which can't come apart. See [BobcatSpec].

BOBCAT029 — a comment read as prose, not a step

Info. The comment "And …" opens with 'And', but no step has opened the narrative in this test, so it is read as an ordinary comment rather than a step. …

When: a comment in a test body starts with And or But before any Given/When/Then comment has opened the narrative.

Why: English sentences start with "And" all the time, and most comments aren't steps. A keyword that can only continue a narrative isn't allowed to start one. Info, because usually the comment really is prose.

Fix: if you meant a step, open with Given, When or Then, or mark it as a keywordless step:

// * the ledger is reconciled

Inside a test that is already narrating, And … is taken as a step. See Marker comments.

BOBCAT032 — table column names no member

Error. For example: The table column 'Town' does not match Address: no 'Town' on Address — it has City, Line1, Zip. Check the spelling, or the member may have been renamed since this spec was written. Variants name a path or a key column, or a [BobcatExamples] column that "names no parameter".

When: a constant table (a literal, a raw string, or a constant interpolated string such as $"| {nameof(Order.Total)} |") or member path names something the type doesn't have. Checked for:

Call	Type checked
PropertyCells.Verify(subject, table) and any (object, StepTable) pair	the subject's static type; dotted paths followed
SetVerificationComparer.Verify(actual, table, keyColumns: …) and any (IEnumerable, StepTable) pair	the element type, top-level columns only; constant key columns too
PartialObjects.FromTable(typeof(T), table)	T — members or constructor parameters, dotted
Specify<T>().With("path", value)	T
Expect.Rows(table) / Expect.NoRowsLike(table) inside a With(…)	the member's element type
[BobcatExamples("…")]	the theory's parameters

Columns match by name or by [Header] title (a title replaces the name). A path that indexes into a collection (Items[0].Sku), a dotted column in a set verification, or a path deeper than 8 levels is refused with its own message.

Why: a stale column is always a broken spec. Catching it in the build beats finding it on the next run.

Fix: correct the column, or write it with nameof so a rename keeps it in step.

When it doesn't fire: a table built at run time, a subject typed object, an interface, an abstract type or a type parameter, and — for a property check or a set — an open class that something derives from (a subclass may carry the column). Those are checked at run time instead: the column becomes an invalid cell that lists what the type does have. See One object against one row and Expected Objects.

BOBCAT033 — no Microsoft.NET.Test.Sdk in an xUnit v3 project

Warning (MSBuild). This xUnit v3 project references no Microsoft.NET.Test.Sdk, so Rider and Visual Studio will find no tests in it (the command line still runs them). …

When: an executable project references xunit.v3 (or xunit.v3.core) but not Microsoft.NET.Test.Sdk. TUnit projects are not checked.

Why: the IDEs discover tests through the VSTest bridge that Microsoft.NET.Test.Sdk and xunit.runner.visualstudio provide. Without them the suite runs from dotnet test and shows nothing in the test explorer.

Fix: add both package references, or set <BobcatSuppressTestSdkWarning>true</BobcatSuppressTestSdkWarning> if the suite only ever runs from the command line. See Getting Started and IDE integration.

BOBCAT034 — an Event Model role names no parameter

Error. From = "cmd" on 'WhenReceived' names no parameter or type parameter of it, so the role is never stamped at any call. It has: command, T. Write it with nameof(…) so a rename keeps the two in step.

When: an [EventModelRole]'s From, or an [EventModelTrigger]'s Route or RouteName, names no parameter of the vocabulary method it decorates (From may also name a type parameter). Reported where the vocabulary is compiled.

Why: at a call site in another assembly the same mistake would just be a role that is never stamped on the slice, with nothing to say so.

Fix: name a real parameter, with nameof:

[EventModelRole(SliceRole.Command, nameof(command))]
[EventModelTrigger(ActTrigger.Http, Route = nameof(route))]
public Task WhenPosted<T>(string route, T command) { /* … */ }

See Binding, not roles.

BOBCAT036 — two specifications share one spec identity

Error. The spec identity 'Orders/order is placed' is also claimed by …. Identity filtering, the resident runner, the flake/duration ledger and the Event Model would treat them as one specification. …

When: two projected tests in one compilation resolve to the same {Feature}/{Scenario} identity: same-named methods in two classes bound to one feature, two method names that read as the same sentence (order_is_placed and order__is_placed), or two data rows of one method that format alike or share a label (1 and 01). Reported at each claimant, naming the others. Compared exactly, case included.

Why: everything keyed on identity would see one spec: running by identity, the resident runner, the ledger, and the Event Model's spec list.

Fix: rename one method, give one an explicit name with [BobcatSpec(Name = "…")], or for rows change or remove the repeated row, or label it with [BobcatExample("label", …)]. Duplicates the compiler can't see together (two assemblies) are reported when the spec manifest is written, and running by such an identity is refused. See Two specs, one identity and An explicit scenario name.

BOBCAT037 — interceptors aren't enabled

Error. This project has N Bobcat step calls to intercept, but interceptors are not enabled for the Bobcat.Generated namespace, so no step would record and a SpecAssert inside a step helper would report to nothing. …

When: the project calls step helpers (or has projected assertions) but Bobcat.Generated isn't in InterceptorsNamespaces. Reported once, at the first call site.

Why: the Bobcat.Generators package adds the opt-in from its buildTransitive props. A ProjectReference to the generator takes no build assets, so it gets the generator without the opt-in. Without it the helpers would run as plain method calls and a failing SpecAssert would land nowhere.

Fix:

<InterceptorsNamespaces>$(InterceptorsNamespaces);Bobcat.Generated</InterceptorsNamespaces>

or import the generator's buildTransitive/Bobcat.Generators.props. See Referencing Bobcat by ProjectReference.

BOBCAT038 — an HTTP act's route can't be known

Info. 'WhenPosted' is this specification's HTTP act, but its 'route' argument is neither a constant nor an interpolated string, so the route is only known at run time. The slice keeps its trigger kind with no route. …

When: the spec's HTTP act (the last act in the test) passes a route the generator can't resolve: a helper call or a variable, a route name no endpoint attribute declares (a minimal API's .WithName), a route name on several endpoints with different templates, or no route at all. An act that takes only the command (WhenPosted(cmd)) gets it when no endpoint attribute takes that command as its body (a minimal API's MapPost), several do with different templates, or none of the act's verb does.

Why: info, because the slice is still right; only the route is missing from the canvas.

Fix: pass the endpoint's route template as a constant ("/api/accounts/{accountId}/deposits", values after it), an interpolated string, or a route name an endpoint attribute declares. Or leave it. See The act's route.

BOBCAT039 — step helper isn't accessible to the interceptor

Error. Step helper 'M' is protected, so Bobcat's generated interceptor cannot call it and its calls would record no step. Make it public or internal.

When: a step helper is protected, private, private protected, or declared on a type the rest of the assembly can't reach (a private nested class). Reported once, at the helper.

Why: the interceptor is generated code outside the class, so it can only call what the assembly can see. Left unintercepted, the helper would open no step.

Fix: make the helper public or internal (protected internal works too). Marker comments have no such constraint. See A decorated helper cannot be protected.

BOBCAT040 — an override of an inherited [BobcatSpec] carries another test attribute

Error. This override inherits [BobcatSpec] from the method it overrides, so with this test attribute too xUnit sees two Fact-derived attributes and fails the test at run time …

When: an override of a test that inherits [BobcatSpec] or [BobcatTheory] carries a different test attribute, usually [Fact(Skip = "…")] to skip one subclass's copy.

Why: xUnit inherits the base method's attribute, so the override has two and fails ("has multiple [Fact]-derived attributes") instead of being skipped.

Fix: stay in the family:

[BobcatSpec(Skip = "not supported by this transport")]
public override Task delivers_in_order() => base.delivers_in_order();

See A test inherited from a shared base.

BOBCAT041 — a specification reaches no Event Model slice

Info. The specification 'Orders/X' is on no Event Model slice: it names no slice and calls no role-stamped vocabulary, so nothing says which slice it describes. Bind it to the slice it describes with [BobcatSpec(typeof(TheCommandOrReadModel))] or [BobcatSpec(SliceName = "...")].

When: only in a suite whose generated Event Model has at least one slice, for a projected spec that:

• is a [BobcatSpec] with no slice binding and no role-stamped vocabulary,
• states only document types, which no slice carries, or
• is unbound, and its feature's other unbound specs make different acts, while its own act is a query or names no command, so it can't be placed without a guess.

Why: info, because the test runs and reports as before; only the model is missing it.

Fix: bind it: [BobcatSpec(typeof(PlaceOrder))] or [BobcatSpec(SliceName = "…")]. A spec on no slice also has no coordinates for bobcat run --slice/--chapter/--domain/--pattern. See An act that names no command.

BOBCAT045 — an act goes through a helper that declares no Event Model role

Info. 'WhenPosted' declares no Event Model role, but it calls 'WhenActing', which is an act, so this call is read as the test's act and its command is taken from the slice binding, AddBook, because the call passes one. Its trigger (an HTTP verb and route) is not read through it. Declare [EventModelRole(SliceRole.Command, nameof(command))] on 'WhenPosted' …

When: a projected spec's last act is a method of the project's own -- usually an HTTP helper on a spec base class, WhenPosted(object command, string url) -- that carries no [EventModelRole], [EventModelTrigger] or [EventModelAct], but whose body calls one that does, and the command it sends is passed in rather than named in its body. The second half of the message says either that the command came from [BobcatSpec(typeof(X))] (the call passes an X), or that which command it sends can't be known, so the slice has no command type.

Why: info, because the slice is already right where it can be: the call is the act, so the slice is never a View, and it is a Command slice when the binding names the command. Before bobcat#681 the act was silently lost and such a spec made a View slice. What can't be recovered is the trigger: the inner act's route is the helper's parameter.

Fix: put the attributes on the helper, naming its own parameters:

[EventModelRole(SliceRole.Command, nameof(command))]
[EventModelTrigger(ActTrigger.Http, Route = nameof(url), HttpMethod = "POST")]
protected Task WhenPosted(object command, string url) => WhenActing(…);

It is not reported for a helper whose own body names its command (OpenTheAccount() => WhenReceived(new OpenAccount(…))): that command and its trigger are read through it. See An act that names no command, and the paragraph before it on helpers.

BOBCAT042 — an inline examples table doesn't fit its theory

Error. For example: Row 2 of [BobcatExamples] on 'discount_is_applied': the cell 'ten' in column 'amount' cannot be read as decimal: …

When: a [BobcatExamples] table the runtime would refuse:

• no header row,
• a parameter with no column and no default value,
• a column given twice,
• a header and no rows,
• a row with the wrong number of cells,
• a cell its parameter's type can't read: a number that doesn't parse, an enum value no member names, NULL or EMPTY for a non-nullable value type.

A column that names no parameter is BOBCAT032.

Why: every one of these would fail the theory before any row runs.

Fix: correct the table:

[BobcatTheory(typeof(ApplyDiscount))]
[BobcatExamples("""
    | amount | tier | expected |
    | 100    | Gold | 90       |
    """)]
public async Task discount_is_applied(decimal amount, Tier tier, decimal expected) { /* … */ }

A cell for a domain type registered with CellValues.Register<T> is left to run time. See A theory's examples as a table.

BOBCAT043 — a Task-returning step is not awaited

Warning. 'ThenDocument' returns Task and is not awaited, so its step runs unobserved: it may finish after the scenario has closed, and a failure in it never fails the test. Add 'await' (and make the test async).

When: a step helper or Event Model vocabulary method ([Given]…[Step], [BobcatStep], [EventModelRole], [EventModelTrigger], [EventModelAct]) that returns a Task or ValueTask is called as a statement, or discarded with _ =, and never awaited: ThenDocument<Order>(id); where await ThenDocument<Order>(id); was meant. A Task that is returned, stored, or passed to Task.WhenAll is not reported.

Why: the spec passes whatever the step finds. The compiler says only CS4014, and only inside an async method. It is not fixed by awaiting every call: some scenario steps are synchronous (ThenEvents), and await on one of those is CS4008.

Fix: add await to the call that was reported, and make the test async if it isn't.

BOBCAT044 — a member check is not one assertion on one member

Error. For example: asserts on 'x.Attendees.ShouldHaveSingleItem().MemberId', which is not a member of the object. A member check is one assertion on one property or field path, …

When: a member check (Specify<T>(x => …), .Check(x => …)) that is not one assertion on one member path:

• chained Shouldly, such as x => x.Attendees.ShouldHaveSingleItem().MemberId.ShouldBe(id),
• an assertion on the object itself (x => x.ShouldNotBeNull()),
• one comparing two members of the same object (x => x.Total.ShouldBe(x.Subtotal)).

Why: Bobcat reads a check as a member path and a value. Without the generator, the run refuses each of these with an ArgumentException that ends the test.

Fix: assert on one member, and specify a collection member's items instead of chaining into them:

Specify<Meeting>().With(x => x.Attendees, Expect.Exactly(Specify<Attendee>().With(a => a.MemberId, theMemberId)));

See member checks.

Retired

These ids are no longer reported by anything. An id is never reused, so a suppression or a search for one keeps meaning one thing.

Ids	Retired with
BOBCAT001–022, BOBCAT030, BOBCAT031, BOBCAT035	the Gherkin lane, removed in 0.50.0 (bobcat#471)
BOBCAT025, BOBCAT026	*.spec-ownership.yaml and the curated Event Model format (bobcat#406)

A <NoWarn> or #pragma for a retired id is harmless and can be deleted.