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test: add Cosmos.Sql.Hedgehog with the generator helpers - #54

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@xperiandri xperiandri commented Oct 11, 2026 •

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Proposed Changes

Depends on #42 (which contains #48) and on #43. The branch starts from one merge commit that joins the branches of #42 and #43, so until both are merged this pull request also shows their commits; its own are the last three. It targets main and not one of those branches, because the build workflow runs only for pull requests into main. The merge commit goes away when the branch is rebased onto a main that has both.

The next step of ADR 0001 (#34, section 22.6): the library that the tests take their generated data from. A generator is Hedgehog's Gen<'T>, a recipe for random values of a type; Hedgehog passes it a size from 1 to 100, and the ranges inside a generator grow with it.

tests/Cosmos.Sql.Hedgehog (assembly FSharp.Azure.Cosmos.Sql.Hedgehog, namespace FSharp.Azure.Cosmos.Tests.Models) starts with the helper modules that need no model. The generators of the SQL syntax tree and the printer laws are the pull request after this one.

Module What it gives
Sample Values outside of a property, for a hand-written test or a dataset. singleWith seed size and multipleWith seed count can be drawn again: the value at index i has the seed seed + i and the size 1 + i % 100, so the values still cover every size. single and multiple draw at a random seed and size.
Gen Optional values. voption and skippable make the absent value rarer as the size grows (weight 2 against 1 + size). optionBalanced, voptionBalanced and skippableBalanced keep it at one draw of two at every size.
CollectionGen immutableArray, immutableHashSet, immutableDictionary, immutableSortedSet, set, map, each with a …Balanced twin that is empty in one draw of two at every size.
TextGen nameString, notes and capitalize, over ASCII letters and digits and by the invariant culture.

Why the balanced twins. The translator has to tell a missing property from a null one and an empty array from a missing one, so test documents need absent values and empty collections often. A sized generator gives them rarely: at the size 100 Gen.voption is absent in 2 draws of 103, and a collection from 0 to 5 elements is almost never empty.

Why the module is called Gen. A file that opens Hedgehog.FSharp and FSharp.Azure.Cosmos.Tests.Models reaches Hedgehog's functions and these through the one name: Gen.int32 … and Gen.voptionBalanced …. The tests are such a file.

Skippable comes from FSharp.SystemTextJson 1.4.36, a new entry in Directory.Packages.props that only this project references.

The project is a library, not a test application. It needs no test framework and no Cosmos test infrastructure, so tests/Directory.Build.props leaves that reference out of it, and the coverage report ignores its assembly.

Types of changes

  • Bugfix (non-breaking change which fixes an issue)
  • New feature (non-breaking change which adds functionality)
  • Breaking change (fix or feature that would cause existing functionality to not work as expected)

Tests only; the packages are unchanged.

Checklist

  • Build and tests pass locally
  • I have added tests that prove my fix is effective or that my feature works (if appropriate)
  • I have added necessary documentation (if appropriate)

Further comments

  • Tests: 16 in tests/Cosmos.Sql.Tests, category Generators, no emulator. Every value is drawn at a fixed seed, so a test sees the same values on every run. "About half" means between 0.4 and 0.6 of 2000 draws, which is nine standard deviations away from one half: it holds for any seed and fails for a generator that favours one outcome.
  • Left out on purpose: the date modules and NumberGen that the ADR lists for this project. Their bounds are "the model's limits" and one reference date, and the test model arrives in Phase 1; written now they would be guesses.
  • Departures from the ADR sketch:
    • multipleWith and multiple return an ImmutableArray, not an array, as the collection rule of this repository asks.
    • The project references no test framework: nothing in it needs one.
  • Verification: dotnet build FSharp.Azure.Cosmos.slnx in Debug and Release with the same 19 warnings as the branches it is built on, none of them in the new project or in the new tests; FSharp.Azure.Cosmos.Sql.Tests 91 of 91 and Hedgehog.MSTest.Tests 143 of 143 in both configurations; Fantomas clean. The emulator suite was not run locally: nothing it uses changed.
  • No changelog entry: tests only.

🤖 Generated with Claude Code

Copilot AI balanced review requested due to automatic review settings October 11, 2026 09:39

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🟡 Changes recommended

Inline JSON conversion silently loses precision for valid non-Int64 numbers.

1 open finding
What changed in this PR

Adds reusable Hedgehog generator helpers for future Cosmos SQL property tests. The stacked prerequisite changes also introduce the SQL model and MSTest Hedgehog adapter.

Changes:

  • Adds sampling, optional-value, collection, and text generators with deterministic tests.
  • Adds prerequisite Cosmos SQL modeling and Hedgehog MSTest infrastructure.
  • Updates build, solution, dependency, documentation, and licensing configuration.
File Description
.github/​copilot-instructions.md Documents new projects and testing conventions.
CHANGELOG.md Records the Cosmos SQL package.
Directory.Packages.props Adds Hedgehog and JSON packages.
FSharp.Azure.Cosmos.slnf Adds projects to the solution filter.
FSharp.Azure.Cosmos.slnx Adds projects to the solution.
THIRD-PARTY-NOTICES.md Adds third-party notices.
build/​build.fs Adds test discovery and coverage exclusions.
src/​Cosmos.Sql/​AssemblyInfo.fs Defines generated assembly metadata.
src/​Cosmos.Sql/​Catalog.fs Implements function lookup and call creation.
src/​Cosmos.Sql/​CatalogData.fs Defines built-in function metadata.
src/​Cosmos.Sql/​EquatableArray.fs Adds structurally equal immutable arrays.
src/​Cosmos.Sql/​FSharp.Azure.Cosmos.Sql.fsproj Defines the SQL library project.
src/​Cosmos.Sql/​FunctionSpec.fs Defines function specifications and errors.
src/​Cosmos.Sql/​ImmutableArrayPatterns.fs Adds immutable-array active patterns.
src/​Cosmos.Sql/​Inline.fs Implements parameter substitution and JSON conversion.
src/​Cosmos.Sql/​Keywords.fs Defines keywords and identifier validation.
src/​Cosmos.Sql/​Printer.fs Implements deterministic SQL printing.
src/​Cosmos.Sql/​Syntax.fs Defines the SQL syntax tree.
src/​Cosmos.Sql/​ValidationError.fs Defines validation diagnostics.
src/​Cosmos.Sql/​Validator.fs Implements SQL semantic validation.
tests/​Cosmos.Sql.Hedgehog/​CollectionGen.fs Adds collection generators.
tests/​Cosmos.Sql.Hedgehog/​FSharp.Azure.Cosmos.Sql.Hedgehog.fsproj Defines the generator library.
tests/​Cosmos.Sql.Hedgehog/​Gen.fs Adds optional-value generators.
tests/​Cosmos.Sql.Hedgehog/​Sample.fs Adds seeded and random sampling helpers.
tests/​Cosmos.Sql.Hedgehog/​TextGen.fs Adds text generators.
tests/​Cosmos.Sql.Tests/​Ast.fs Adds concise test AST builders.
tests/​Cosmos.Sql.Tests/​CatalogTests.fs Tests function catalog behavior.
tests/​Cosmos.Sql.Tests/​EquatableArrayTests.fs Tests structural array behavior.
tests/​Cosmos.Sql.Tests/​FSharp.Azure.Cosmos.Sql.Tests.fsproj Defines SQL unit tests.
tests/​Cosmos.Sql.Tests/​GeneratorHelperTests.fs Tests generator distributions and bounds.
tests/​Cosmos.Sql.Tests/​InlineTests.fs Tests inline parameter substitution.
tests/​Cosmos.Sql.Tests/​PrinterTests.fs Tests SQL printer output.
tests/​Cosmos.Sql.Tests/​SyntaxTests.fs Tests syntax-tree equality.
tests/​Cosmos.Sql.Tests/​TestCategories.fs Defines SQL test categories.
tests/​Cosmos.Sql.Tests/​ValidatorTests.fs Tests SQL validation rules.
tests/​Cosmos.Sql.Tests/​testconfig.json Enables method-level parallelism.
tests/​Directory.Build.props Excludes independent helper projects from infrastructure.
tests/​Hedgehog.MSTest.Tests/​Common.fs Adds shared adapter-test fixtures.
tests/​Hedgehog.MSTest.Tests/​GenAttributePreludeTests.fs Tests built-in generator attributes.
tests/​Hedgehog.MSTest.Tests/​Harness.fs Adds an adapter execution harness.
tests/​Hedgehog.MSTest.Tests/​Hedgehog.MSTest.Tests.fsproj Defines the adapter test suite.
tests/​Hedgehog.MSTest.Tests/​MSTestTests.fs Tests MSTest-specific behavior.
tests/​Hedgehog.MSTest.Tests/​PropertyTests.fs Tests property execution and configuration.
tests/​Hedgehog.MSTest.Tests/​testconfig.json Configures adapter-test parallelism.
tests/​Hedgehog.MSTest/​AutoGenConfig.fs Resolves automatic generator configurations.
tests/​Hedgehog.MSTest/​GenAttribute.Prelude.fs Adds standard generator attributes.
tests/​Hedgehog.MSTest/​GenAttribute.fs Defines custom generator attributes.
tests/​Hedgehog.MSTest/​Hedgehog.MSTest.fsproj Defines the MSTest adapter project.
tests/​Hedgehog.MSTest/​InternalLogic.fs Runs and reports properties.
tests/​Hedgehog.MSTest/​IPropertyAttribute.fs Defines shared property settings.
tests/​Hedgehog.MSTest/​KnownTypes.fs Caches reflected framework types.
tests/​Hedgehog.MSTest/​Prelude.fs Adds adapter helper functions.
tests/​Hedgehog.MSTest/​PropertiesAttribute.fs Defines class-level property settings.
tests/​Hedgehog.MSTest/​PropertyAttribute.fs Integrates properties with MSTest.
tests/​Hedgehog.MSTest/​PropertyContext.fs Merges property configuration.
tests/​Hedgehog.MSTest/​RecheckAttribute.fs Adds counterexample replay metadata.
tests/​Hedgehog.MSTest/​ReflectionHelpers.fs Adds return-type reflection helpers.

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Comment thread src/Cosmos.Sql/Inline.fs
xperiandri and others added 7 commits October 11, 2026 12:42
Start the Hedgehog MSTest adapter, tests/Hedgehog.MSTest (ADR 0001,
sections 5, 14 and 22.6), with the nine files that Hedgehog.NUnit and
Hedgehog.Xunit of hedgehogqa/fsharp-hedgehog share and that do not
depend on a test framework: Prelude, ReflectionHelpers, AutoGenConfig,
IPropertyAttribute, RecheckAttribute, GenAttribute, GenAttribute.Prelude,
PropertyContext and InternalLogic, copied from src/Hedgehog.NUnit at the
Hedgehog 2.0.4 release commit a469772 in upstream's file layout and
compile order. The only change is the namespace, Hedgehog.NUnit becomes
Hedgehog.MSTest, so this commit can be compared with upstream line by
line; the MSTest attribute and the changes it needs follow separately.

The code is Apache-2.0: every copied file names its origin, the
copyright and the license in a header comment, and the new
THIRD-PARTY-NOTICES.md records the source, the commit, the files and the
license text.

The same code is proposed upstream as src/Hedgehog.MSTest, so the
project keeps upstream's conventions rather than the repository's:
nullness checking is off (upstream enables it nowhere, and the copied
files give 23 nullness warnings under the repository's Nullable=enable)
and .fantomasignore excludes the project, so the Fantomas run of the
build leaves upstream's formatting alone. It sets IsTestProject=false
and IsPackable=false, because tests/Directory.Build.props marks every
project under tests/ as a test project, references MSTest.TestFramework
rather than the MSTest metapackage, and is excluded from the test
infrastructure reference of tests/Directory.Build.props, because the
adapter must not depend on this repository.

The copied code calls functions of FSharp.Core that return an option,
such as Seq.tryHead and Seq.tryFind. The collection helpers that the
root Directory.Build.props compiles into every F# project replace
exactly these functions with ones that return a voption, so the project
removes that file from its compilation for now; the commit that moves
the adapter to the repository's conventions takes the removal out.

The project joins both FSharp.Azure.Cosmos.slnx and
FSharp.Azure.Cosmos.slnf, which FAKE builds, so every build compiles it,
and THIRD-PARTY-NOTICES.md joins the solution items.
Directory.Packages.props gets Hedgehog 2.0.4 (Apache-2.0; FSharp.Core
>= 8.0.403 and TypeShape 9.0.0 transitively, checked in the nuspec),
which contains the former Hedgehog.Experimental auto-generation.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Turn the ported sources into an MSTest adapter (ADR 0001, section 22.6).
PropertyAttribute derives from TestMethodAttribute and, like it, applies
to methods only and is not inherited. It keeps upstream's six
constructor overloads and named settings (AutoGenConfig,
AutoGenConfigArgs, Tests, Shrinks, Size), forwards the caller
information of every constructor to the base constructor, as
STATestMethodAttribute does, and overrides ExecuteAsync. MSTest has no
counterpart to NUnit's test builder or xUnit's discoverer, so this one
attribute is the framework layer; PropertiesAttribute is copied from
upstream with the same settings.

Each generated case and each shrink step is one call of
ITestMethod.InvokeAsync, never MethodInfo.Invoke, so MSTest creates the
test class, injects the TestContext and runs TestInitialize, TestCleanup
and Dispose for every case, and applies a [<Timeout>] to each of them.
The values of a [<DataRow>] or [<DynamicData>] row, which MSTest passes
in ITestMethod.Arguments, are the leading arguments and also appear in
the report; only the parameters after them are generated. Generated
IDisposable arguments are disposed after their invocation. The run is
folded into one TestResult, because several results from one
ExecuteAsync appear as separate results of one test: a failure carries
Hedgehog's report with the shrunk arguments, the exception of the
counterexample as inner exception (unwrapped from MSTest's internal
TestFailedException), the output of its invocation and a
[<Recheck("...")>] to add next to the method's Property attribute,
which keeps the attribute's settings, such as its AutoGenConfig, so that
the recheck data replays this counterexample. A run that gives up after
Hedgehog's 100 discards fails, as in upstream.

Additions beyond upstream: a uint64 Seed setting on both attributes;
Assert.Inconclusive in an invocation discards the case, and fails it
while rechecking, because a recheck cannot discard its only case; a run
whose TestContext cancellation token is cancelled stops without
shrinking, reading the token before every invocation, because MSTest
gives the TestContext a new token source before each TestCleanup, and
checking it again after the invocation, whatever its outcome: MSTest
reports a test method that returns without observing its cancelled
token as passed, and after the last case nothing else would notice the
token, so the property stops in the same way wherever the cancellation
reached it; the run still disposes the arguments generated for a case
it keeps from running;
an invocation whose outcome is none of Passed, Failed, Inconclusive and
Timeout, such as Error, was not run as a test by MSTest, so the run
stops at it without shrinking and the property reports the outcome and
the exception of that invocation instead of a counterexample.
The token comes from TestContext.Current, experimental in MSTest 4.2.3
(MSTESTEXP), in one helper with a scoped #nowarn "57".

Departures from upstream, each recorded in the header of the changed
file: class settings come from the reflected type of the method, so a
property inherited from an abstract base gets the settings of each
derived test class, and a derived class's [<Properties>] win over its
base's; a GenAttribute is found through a new non-generic GenAttribute
base wherever it sits in the inheritance chain (upstream checks only the
direct base type and silently auto-generates otherwise); generic
methods, which MSTest 4.2.3 discovers, and return types other than unit,
Task and ValueTask, which MSTest 4 cannot discover, are rejected before
any generator is built, so the return-value handling and the
reflection-based invocation of upstream's InternalLogic and
ReflectionHelpers are removed; every invocation is memoised per
shrink-tree node, because Hedgehog 2.0.4 runs an asynchronous case again
whenever it unwraps it and would invoke the counterexample a second time
to read its journal; the recheck, which is synchronous in Hedgehog
2.0.4, runs on the thread pool; the generic arguments of an
AutoGenConfig method are inferred from every place a generic parameter
occurs in its parameter types, nested ones such as 'a[] included, and
every place must give the same type, where upstream takes one argument
type per parameter that is itself a generic parameter, which fails for
'a list or a repeated 'a; NonZeroInt skips a 0 at either end of its
range, where upstream generates from an empty part, and rejects the
range from 0 to 0; Odd and Even are generated from the odd or even
values inside their range and reject a range without one, where
upstream sets or clears the lowest bit of any value of the range and
so leaves an even upper bound of Odd or an odd lower bound of Even by
one; any exception, an invalid AutoGenConfig
type or malformed recheck data included, becomes a result with the
outcome Error instead of escaping ExecuteAsync.

InternalLogic.executeAsync, a function from the method, the data row,
an invoker and a function that reads the cancellation token to a
TestResult, is the entry point of ExecuteAsync; InternalsVisibleTo
exposes it to the adapter's suite, so the suite can run properties that
fail by design without failing itself. The repository turns
GenerateAssemblyInfo off for the FAKE-written AssemblyInfo.fs of the src
projects, so this project turns it back on for the SDK to emit the
InternalsVisibleTo attribute.

Every public type and member is documented, and every reference to a
type or member is a documentation ID that resolves in the documentation
files of the referenced assemblies, including the primary constructors,
whose comments sit before their parameters. THIRD-PARTY-NOTICES.md lists
the two attribute files.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The adapter was ported in upstream's style, because the same code was to
go into the upstream pull request. That pull request now exists,
hedgehogqa/fsharp-hedgehog#487, with its own copy in upstream's style,
so the copy in this repository follows the coding guidelines of this
repository, its formatting and nullness checking included, as the
review of #43 asks:

- A setting that is not given is a voption instead of an option: the
  members of IPropertyAttribute, the fields of PropertyContext, the
  private constructors and fields of PropertyAttribute and
  PropertiesAttribute, the generic arguments that AutoGenConfig infers
  and the generator that a GenAttribute gives.
- The project compiles src/Shared/ValueCollections.fs again, like every
  other F# project, and uses its Seq.tryHead, Seq.tryFind,
  Seq.tryExactlyOne and Seq.zip, which return a voption or struct
  tuples. The three files that use them open FSharp.Azure.Cosmos, the
  namespace of these functions. Prelude loses Option.requireSome and
  Seq.seqTryExactlyOne.
- The generated arguments are an array instead of a list. Hedgehog 2.0.4
  has Gen.sequence for sequences and Gen.sequenceList for lists, both
  over one traversal, and nothing for arrays, so Prelude adds
  Gen.sequenceArray over Gen.sequence; the values shrink as they did
  through Gen.sequenceList. Type.getAllAttributes returns an array, and
  the two parts of a NonZeroInt range are an array.
- Collections are joined in array and sequence expressions instead of
  Array.append and Seq.append: the arguments of an invocation, the
  values of the journal and the attributes that PropertyContext folds.
- The types that the adapter compares other types with are in one
  module, KnownTypes: Void, Task, ValueTask, IAutoGenConfig and the
  generic definitions of ValueTask<'T>, Async<'T> and Result<'T, 'E>.
  typeof is one ldtoken, but typedefof calls GetGenericTypeDefinition
  on every use (read in the compiled IL), so each type is resolved
  once, and every comparison goes through the operators of System.Type
  instead of generic equality.
- withTests, withShrinks and withSeed are functions with named
  parameters instead of values that hold a lambda.
- Attributes are found through GetCustomAttributes<'T> and OfType<'T>
  instead of a type test and a cast per attribute.
- The error for an AutoGenConfig type without exactly one config member
  says "member" where upstream says "property": a method that takes
  AutoGenConfigArgs is accepted as well (automatic review of #50).

- The project is formatted with Fantomas: .fantomasignore no longer
  lists it, so the Fantomas run of the build covers it.
- Nullness checking is on, as everywhere in the repository. A data row
  and the arguments of an invocation or of a config method may hold
  null, so they are arrays of objnull. A null array is checked for where
  it enters: in the setters of AutoGenConfigArgs, which take it as no
  arguments, and at the entry point that receives the data row from
  MSTest. Nested exceptions and base types are matched on null instead
  of tested with isNull, reflection lookups that cannot fail are
  asserted with nonNull, and a config method that returns no
  IAutoGenConfig is an error. One call keeps a
  scoped #nowarn "3261", in a helper of its own:
  ITestMethod.InvokeAsync declares the elements of its arguments as
  non-null, although MSTest itself passes it ITestMethod.Arguments,
  whose elements it declares as nullable.
- The pipeline that builds the journal ends in Seq.toArray, so that it
  stays in one module.

The header of every changed file records the change.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Add tests/Hedgehog.MSTest.Tests, an MSTest runner executable (OutputType
Exe, EnableMSTestRunner) with method-level parallelism in
testconfig.json, that runs 137 tests against the adapter (ADR 0001,
section 22.6).

Upstream's F# xUnit and NUnit adapter tests at a469772 are rewritten as
[<TestClass>] types: generating and shrinking, AutoGenConfig types and
their error messages, AutoGenConfigArgs with generic, concrete and mixed
arguments, class-level settings and their overrides, attribute
subclasses, tuples, shrink limits, recheck data and Size, IDisposable
arguments, GenAttribute and the 18 built-in generator attributes. The
cases MSTest 4 cannot discover (bool, Result, Async, Task<'T> and
Property returns, unresolved generics, module-level properties) and the
xUnit-specific ones are left out. Added to them are tests of a generic
config parameter used for two arguments, nested in an array type and
given two types, of NonZeroInt with 0 at either end of its range and
from 0 to 0, and of Odd and Even at the ends of their range, next to
Int32.MinValue and Int32.MaxValue and over a range without such a
value; three misspelled test names are corrected. The ported
files and the shared
configurations carry upstream's Apache-2.0 attribution, and
THIRD-PARTY-NOTICES.md lists them. The targets that must shrink exactly
once fix their seed: with a random one, a run whose first failing value
is exactly 2500 has nothing smaller to shrink to, which happened in 8 of
20,000 simulated runs.

MSTest-specific tests cover what the adapter adds or does differently,
each pinning MSTest behaviour that the adapter relies on: a new
instance, TestContext, TestInitialize, TestCleanup and Dispose for every
case, with property and constructor injection; DataRow, DynamicData and
TestDataRow<struct (string * int)> rows as leading arguments; a property
inherited from an abstract base reading the settings of each derived
test class, and a derived class's settings and configuration winning
over its base's; a GenAttribute derived from a built-in one; the caller
information of each of the six PropertyAttribute constructors; Task and
ValueTask bodies; Assert.Inconclusive as a discard and as a failure
while rechecking; give-ups failing; generic methods and unsupported
return types giving an error result; the same Seed giving the same
cases; the counterexample invoked once; a token cancelled at a failing
case that has smaller values to shrink to, and a timed-out invocation,
stopping the run without shrinking, with a per-invocation [<Timeout>]
that a whole property exceeds and a TestCleanup that makes MSTest
replace the token source; a token cancelled during a passing
invocation, an earlier one or the last, stopping the run as well; the
arguments of a case that a cancelled
token keeps from running still disposed; an invocation that ends with
the outcome Error or NotFound, and an exception of the invoker itself,
stopping the run without shrinking and giving the property that outcome
and that exception instead of a failure.

Properties that fail by design never fail the suite. Targets in classes
without [<TestClass>], which MSTest does not run, go through Harness and
the adapter's entry point InternalLogic.executeAsync with an invoker
that creates the class and awaits the method, so the tests inspect the
report, the journal and the result. FailingPropertyAttribute runs a
property through the real MSTest pipeline instead and passes when its
single result has the expected outcome, message, output and inner
exception: a failure reports its counterexample, its recheck data and
the output of its invocation, [<Recheck>] replays the counterexample of
the seed-42 run and passes once the bug is fixed, a data row appears
among the parameters, malformed recheck data gives an error result and
a give-up fails. Twenty behaviours of the adapter, from the reflected
type and the memoised invocations to the single result and the
cancellation check before each invocation, were each reverted in the
adapter on its own: a test fails for every one. So do the three tests of
an invocation that MSTest could not run when such an outcome is treated
as a falsified case again.

Like the adapter, the suite follows the coding guidelines of this
repository, its formatting and nullness checking included; one test
pins that a null array of AutoGenConfigArgs, which a caller compiled
without nullness checking can give, counts as no arguments. The suite
compiles the collection helpers of src/Shared/ValueCollections.fs and
references no project of this repository but the adapter, so
tests/Directory.Build.props leaves the Cosmos test infrastructure out of
it too. The suite joins both
FSharp.Azure.Cosmos.slnx and FSharp.Azure.Cosmos.slnf; testsGlob,
already narrowed to tests/**/*.Tests.??proj, picks it up and leaves the
adapter library out, so DotnetTest runs Hedgehog.MSTest.Tests next to
FSharp.Azure.Cosmos.Tests. The coverage report excludes the adapter and
Hedgehog, which the suite loads and whose package embeds its PDB.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
…hog MSTest adapter

Hedgehog 2.0.4 cannot auto-generate a DateOnly or a TimeOnly: Gen.auto
throws for both (run in dotnet fsi against the package), and upstream's
adapters have a generator attribute for DateTime and DateTimeOffset
only. A property with a parameter of one of these types therefore
needed a generator of its own; the review of #43 asks for the two
attributes.

DateOnlyAttribute generates a date between two dates, both included,
and TimeOnlyAttribute a time of day between two times, both included,
at the precision of TimeOnly (100 nanoseconds). Both ranges are
constant, like those of DateTimeAttribute: they do not grow with the
size of a case, and a value shrinks towards the lower end. Without
arguments DateOnly generates within the 3650 days from 2000-01-01, the
dates of DateTimeAttribute's default range, and TimeOnly any time of
day. An attribute argument cannot be a DateOnly or a TimeOnly, so each
attribute also takes its range as integers,
[<DateOnly(2024, 2, 28, 2024, 3, 1)>] and [<TimeOnly(9, 0, 17, 30)>];
the constructor that takes the two values themselves serves attributes
that derive from these.

Six tests cover the default and the given ranges through [<Property>]
methods and check on 200 sampled values that a range of three values
gives each of them, both ends included, and nothing else.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
… them

A new DotnetListTests target, between DotnetBuild and DotnetTest in
both build chains, runs `dotnet test --list-tests` for every test
application (ADR 0001, section 22.1). MSTest 4 fails the discovery of a
whole assembly when one test method has a signature it cannot run, such
as a [<Property>] method that returns bool, while the F# build gives no
warning; checked by adding such a method to the adapter's suite: the
build succeeded without a warning, and the listing failed with UTA007
and exit code -532462766. Listing reports that before the run, which
needs the emulator, starts.

DotnetTest and DotnetListTests share dotnetTestApplications, which runs
`dotnet test --no-build` in the configuration of the executing targets
for every project that testsGlob matches, so the loop over the test
applications is written once.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The solution tree of the agent instructions lists tests/Hedgehog.MSTest
and its suite, and the libraries list Hedgehog. The testing rules say
how to write a property test: a method of a [<TestClass>] type marked
[<Property>], with generated parameters, never Property.check inside a
[<TestMethod>]; that it is an instance method that returns unit, Task or
ValueTask and fails by throwing, because MSTest 4 rejects static methods
and other return types and one such method fails the discovery of the
whole assembly, which --list-tests shows before a run; that MSTest runs
[<TestInitialize>] and [<TestCleanup>] for every generated case and
every shrink step; and that a failure reports a [<Recheck>] that
replays it; and that a DateOnly or TimeOnly parameter needs its
generator attribute, because Hedgehog 2.0.4 cannot auto-generate these
types. They also record that the adapter and its suite are the
exception to the shared test infrastructure reference, the suite
referencing the adapter alone, and that their code follows the rules of
the file, formatting and nullness checking included, while the copy in
the upstream pull request keeps upstream's style, with Apache-2.0
headers and THIRD-PARTY-NOTICES.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
@xperiandri
xperiandri force-pushed the test/cosmos-sql-hedgehog branch from b40f6f2 to 97acd6a Compare October 11, 2026 11:09
xperiandri and others added 2 commits October 11, 2026 13:46
…mutableArray` patterns

Starts src/Cosmos.Sql (FSharp.Azure.Cosmos.Sql, net10.0, FSharp.Core
only), the project of the Cosmos DB SQL model of ADR 0001 (sections 4, 6
and 15), with the two collection helpers that the syntax tree is built
from, so that they can be reviewed on their own before the tree, the
printer and the validator follow.

EquatableArray<'T> is a struct over ImmutableArray<'T> with sequence
equality and a combined hash code. ImmutableArray's own Equals and
EqualityComparer<T>.Default compare the reference of the wrapped array,
which a struct tuple, a default-comparer HashSet or a C# caller would
see, and a default array never equals an empty one. The nodes of the
syntax tree will hold their children in this wrapper, so that their
equality is structural under every comparer. The EquatableArray module
creates and maps the arrays; its unsafeOfArray wraps an array without
copying it, as ImmutableCollectionsMarshal.AsImmutableArray does, for a
caller that gives the array away. Implicit conversions to and from
ImmutableArray wrap and unwrap without copying; F# applies them without
a warning at method arguments, and with warning FS3391 elsewhere.

The struct partial active patterns Arr0, Arr1, Arr2, Arr3 and ArrN match
an ImmutableArray by its length without allocating: each returns a
struct value option or a bool, and its payload is a struct tuple.

tests/Cosmos.Sql.Tests is the new emulator-free MSTest project, with 15
tests under the category Collections: a file for the struct, one for the
module and one for the patterns. Both projects join the solution and the
solution filter, and the agent instructions list them. The library is
not packed yet (IsPackable is false): a push to main publishes every
packable project to GitHub Packages, and the collection types alone are
no package. The commit that gives the package its metadata removes the
setting.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Adds the syntax tree of the Cosmos DB NoSQL query language to
FSharp.Azure.Cosmos.Sql: one union case or record per non-terminal of the SDK
grammar sql.g4, named after the SDK's SqlObjects classes (ADR 0001 sections 6
and 15). There is no case for raw text and no shift operator; integer literals
are int64 and numbers keep the SDK's integer/double split.

Child sequences are EquatableArray<'T>, so the equality of the tree is
structural under every comparer. SyntaxTests checks it on whole trees:
separately built trees with equal children are equal, hash alike and find each
other as dictionary keys, which the plan cache needs.

Keywords holds the reserved words of the grammar and its identifier rule.
THIRD-PARTY-NOTICES.md attributes the material taken from the Azure Cosmos DB
.NET SDK (MIT) and joins the solution items.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
xperiandri and others added 9 commits October 11, 2026 14:56
Printer writes the syntax tree as query text following the rules of the SDK's
SqlObjectTextSerializer without pretty printing (ADR 0001 section 6): bare
aliases; property accesses as alias["name"] with JSON escaping, or alias.name
under PropertyStyle.DotWhenSafe when the name is a safe identifier; every
binary, unary, conditional, coalesce, IN, BETWEEN and LIKE expression in
parentheses; the SDK's string escaping (the solidus stays as is, like in the
SDK); integers in full and other numbers with "R", both in the invariant
culture; lower-case literal keywords; the udf. prefix; the clause order of the
grammar. The text equals the SDK baselines after whitespace normalization; it
differs only where the SDK writes "NOT  LIKE" and a space after GROUP BY.

Printing is total and has two modes: print writes parameters as @name, while
printInline and printPredicateInline first run Inline.substituteParameters,
which replaces every parameter, in every clause and subquery, with the
constant an encoder gives for it. The encoder contract is one function from a
parameter name to the literal, if any; Inline.ofJsonElement turns a value
written by a serializer into such a literal. printPredicate writes the
"FROM c WHERE ..." text that the filter predicate of a patch takes. Errors of
the substitution are ValidationError values.

The golden tests cover every node kind and cite the SDK baselines they
reproduce (SqlObjectVisitorBaselineTests, the parser baselines and the LINQ
baselines of SDK 3.62.0), escaping of every control character, and culture
independence under fr-FR and a culture with other number symbols.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The built-in functions of the query language are data (ADR 0001 section 6): a
FunctionSpec per name with category, arity, return kind, undefined rule,
index usage, availability, determinism, the ORDER BY and ORDER BY RANK flags,
the Learn page and a status. CatalogData.fs is the data file; Catalog exposes
it as Catalog.all, Catalog.byName (a FrozenDictionary with OrdinalIgnoreCase,
since function names are case-insensitive), Catalog.tryFind and Catalog.call,
which builds a call with the catalog's spelling after checking that the
function is known, specified and given an accepted number of arguments.

The catalog is seeded with every name of SqlFunctionCallScalarExpression.Names
of SDK 3.62.0 except the internal ones that start with an underscore, plus the
documented names the SDK does not list: the INTBIT* spellings, NOW, AGO,
NUMBERBIN, REGEXREPLACE, REGEXREPLACEALL, ST_AREA and the GETCURRENT*STATIC
functions. The functions the first translator slice needs are specified from
their Learn pages (type checks, the string and array functions, aggregates,
IIF, the integer functions, basic date and time functions, and the scoring
functions VectorDistance, FullTextScore and RRF); every other entry is
Unsupported with its reason: not specified yet, undocumented, a keyword of
the grammar or the SDK's spelling of a documented name.

A test reads the names of the SDK in use by reflection and fails when an SDK
update adds or removes one; the test project references Microsoft.Azure.Cosmos
for it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
SqlQuery.validate and SqlQuery.validateWith check a query and its subqueries
against the rules of the query language that the grammar cannot express and
return them as ImmutableArray<ValidationError>, each with a code and an
English message that quotes the offending fragment (ADR 0001 section 6). The
rules are those the first translator slice needs:

- SELECT * only with exactly one collection in the FROM clause;
- TOP never in a subquery;
- no parameter in a GROUP BY key or as an ORDER BY key, while the arguments
  of a function allowed in ORDER BY or ORDER BY RANK may be parameters, as
  the vector and hybrid search queries on Microsoft Learn and the SDK's
  query plan baseline pass the query vector; parameter names of the form
  @name;
- ORDER BY items only property paths or calls of functions the catalog
  allows in ORDER BY; ORDER BY RANK items only scoring functions; functions
  allowed only in ORDER BY RANK nowhere else;
- identifiers of the form [A-Za-z_][A-Za-z_0-9]* that are not reserved words;
- non-empty IN lists and select lists;
- built-in functions known to the catalog and called with an accepted arity;
- finite number literals, integer literals within -2^53..2^53 unless
  ValidationOptions.AllowLossyInt64 is set, non-negative counts.

OFFSET and LIMIT together, counts as literals or parameters, string object
keys and the separation of plain and rank ORDER BY items hold by construction
of the syntax tree. The documentation of the tree, the keywords, the printer
and the catalog now refers to the rules the validator checks.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Gives the new package its NuGet metadata and packs THIRD-PARTY-NOTICES.md
next to README.md and LICENSE, because the package contains material derived
from the Azure Cosmos DB .NET SDK (ADR 0001 section 5). The package depends on
FSharp.Core only; System.Text.Json is in-box on net10.0. IsPackable=false,
which kept the library out of the packages while it held the collection types
only, is removed.

The project is already part of the solution filter that FAKE packs, the test
glob tests/**/*.Tests.??proj picks up the new test project, the coverage
assembly filter "-*.Tests;-*.Tests.Infrastructure" excludes it while keeping
the library, and fsdocs builds the API documentation of every src project.
The changelog lists the package under Unreleased.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
…ions

The solution tree of the agent instructions names every file of
src/Cosmos.Sql with what it holds, in compile order, as it does for
src/Cosmos.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The generators of the SQL model and the printer laws need both: the
syntax tree, printer and validator of #42 and the property attribute of
#43. This merge is only the base of the stacked branch; it goes away
when both pull requests are in main and the branch is rebased onto it.

THIRD-PARTY-NOTICES.md is added by both; the result keeps the text of
#42 and appends the fsharp-hedgehog section of #43.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
tests/Cosmos.Sql.Hedgehog is the library that the generator projects of
ADR 0001 (section 22.6) share. This commit adds the helper modules that
need no model, in the namespace FSharp.Azure.Cosmos.Tests.Models:

- Sample draws values outside of a property. singleWith and multipleWith
  take a seed, so that the data of a dataset or of a data-driven test can
  be drawn again: the value at index i has the seed seed + i and the size
  1 + i % 100, which keeps the values spread over every size. single and
  multiple draw at a random seed and a random size.
- Gen generates optional values: the sized voption and skippable, where
  an absent value becomes rarer as the size grows, and optionBalanced,
  voptionBalanced and skippableBalanced, where it stays as likely as a
  present one. The module has the name of Hedgehog's own on purpose: a
  file that opens both namespaces reaches both through Gen.
- CollectionGen generates immutable arrays, hash sets, dictionaries and
  sorted sets, F# sets and maps, each with a Balanced twin that is empty
  in one draw of two at every size.
- TextGen generates names and notes of ASCII letters and digits, and
  capitalizes by the invariant culture.

Skippable comes from FSharp.SystemTextJson 1.4.36, which only this
project references. The date and number helpers of the ADR are left for
the step that brings the test model: their bounds are that model's.

The project is a library, not a test application, and needs neither a
test framework nor the Cosmos test infrastructure, so the shared props
of the test projects leave that reference out of it, and the coverage
report ignores its assembly.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Sixteen emulator-free tests in the category Generators. Every value is
drawn at a fixed seed, so a test sees the same values on every run:

- the seeded members of Sample give the same values again, the value at
  index i has the seed and the size the documentation states, and the
  random members draw at a size from 1 to 100;
- the balanced generators give the absent value, or the empty
  collection, in about half of 2000 draws at the smallest and the
  largest size, while the sized ones go from one half at the size 1 to
  a few draws in a hundred at the size 100;
- the collections run from empty to their largest size, and a key that
  repeats keeps one entry of a dictionary or a map;
- capitalize gives "Istanbul" while the current culture is Turkish, and
  names and notes keep to their lengths and to ASCII letters and digits.

The bounds of "about half" are 0.4 and 0.6: nine standard deviations of
a share counted over 2000 draws, so they hold for any seed and still
fail for a generator that favours one outcome.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The solution tree lists tests/Cosmos.Sql.Hedgehog, and the testing
section says where generators live, which Sample members give data that
can be drawn again, what the Balanced suffix means, what a generator
file opens and how its parameters are named, and that a generator makes
valid values by construction.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
@xperiandri
xperiandri force-pushed the test/cosmos-sql-hedgehog branch from ae3f267 to 32bdbb0 Compare October 11, 2026 13:07

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