configuration.md

BabyBehave Configuration Reference

This document lists every compile-time #define and runtime environment variable that BabyBehave recognizes. Most consumers can ignore these and use the defaults, but they are available for special cases (pure C++17 builds, CI/CD output formatting, namespace collisions, etc.).

Compile-time #define options

Define any of these before #include <BabyBehave/bdd.hpp> to change compile-time behavior.

BABYBEHAVE_DISABLE_GHERKIN

Since: v0.8.0
Default: Not defined (Gherkin is ON by default)
Type: Compile-time gate

Disables Gherkin support, removing the BabyBehave::BDD::Gherkin namespace and the C++20-specific #include directives (<concepts>, <optional>, etc.) that it depends on.

When to use: For projects targeting pure C++17 that do not need Gherkin .feature file parsing. The rest of BabyBehave's C++17-compatible API (fluent BDD macros, matchers, reporters) remains fully available.

Example:

#define BABYBEHAVE_DISABLE_GHERKIN
#include <BabyBehave/bdd.hpp>

// BabyBehave::BDD::Gherkin is NOT defined; everything else works normally
using namespace BabyBehave::BDD;

bool MyStep(TestContext& ctx) { return true; }

int main() {
    Given(MyStep);
}

Impact: Removes ~1400 lines (roughly 30% of bdd.hpp's total). Compile-time and runtime cost: zero when disabled (no template instantiations, no extra symbols, no extra #includes).

---

BABYBEHAVE_NO_SHORT_MACROS

Since: v0.7.0
Default: Not defined (short macros are defined)
Type: Compile-time gate

Disables the short, generic macro aliases (Given, With, When, Then, And, Or, But, and their -I variants like WithI, WhenI, etc.).

When to use: Your codebase or another library already uses names like When, Then, And, etc., causing a collision. BabyBehave's underlying functions (GivenAImpl(), AddStep<StepType>()) are still available; you just use them directly instead of through the convenience macros.

Example (no collision):

#include <BabyBehave/bdd.hpp>

using namespace BabyBehave::BDD;

bool MyStep(TestContext& ctx) { return true; }

int main() {
    Given(MyStep).When(MyStep).Then(MyStep);  // Works
}

Example (with collision):

#define BABYBEHAVE_NO_SHORT_MACROS
#include <BabyBehave/bdd.hpp>

// Some library also defines When, Then, etc. (no conflict now)

using namespace BabyBehave::BDD;

bool MyStep(TestContext& ctx) { return true; }

int main() {
    GivenAImpl("setup", MyStep)
        .AddStep<Precondition>("precondition", MyStep)
        .AddStep<Action>("action", MyStep)
        .AddStep<Postcondition>("postcondition", MyStep);
}

For a more detailed example, see examples/NoShortMacros.cpp.

---

Runtime environment variables

Set these at test execution time (via your test runner, shell, or set_tests_properties() in CMake) to control runtime behavior.

BABYBEHAVE_QUIET

Since: v0.7.0
Default: Not set (narration is enabled)
Type: Runtime toggle
Valid values: "0", empty string, or any other string

Controls whether step narration (the human-readable output describing what each scenario is testing) is printed to stdout.

Value	Behavior
Not set (unset)	Narration is printed (ON)
"" (empty)	Narration is printed (ON)
"0" (zero)	Narration is printed (ON)
Any other string (including "1", "true", etc.)	Narration is silenced (OFF)

When to use: In CI/CD pipelines where test output must be machine-readable or concise (e.g., before piping through grep, or in a logging system that already captures test names). Also useful when running many tests in parallel and the interleaved narration becomes unreadable.

Example (bash):

# Silence narration for this test run
BABYBEHAVE_QUIET=1 ./my_test_binary

# Or set it for ctest
ctest --test-dir build/bb-release -E ".*" -DBABYBEHAVE_QUIET=1

Example (CMake set_tests_properties):

add_executable(my_test my_test.cpp)
set_tests_properties(my_test PROPERTIES
    ENVIRONMENT "BABYBEHAVE_QUIET=1"
)

Note: The SetNarrationEnabled() runtime API in bdd.hpp can override this flag at any point during test execution — useful if you want to enable/disable narration within your test code itself (e.g., for specific test categories).

---

BABYBEHAVE_STYLE

Since: v0.7.0
Default: "plain" (when unset)
Type: Runtime selection
Valid values: "plain", "arrow", "tree", or unset

Selects which narration style BabyBehave uses when printing step output. All styles produce semantically identical results; they differ only in how they format the output.

Style	Output format	Use case
"plain" (default)	Steps printed live as they run, one line per step	CI logs, real-time feedback, default
"arrow"	Buffered output with -> prefix for each step, printed once per scenario	Compact, structured, Gherkin-like alignment
"tree"	Buffered output with a tree structure (primary steps at top level, detail steps nested)	Hierarchical visualization, reading comprehension

When to use: Choose based on how you want the test output formatted. Most consumers can leave it unset and use the default plain style.

Example (bash):

# Use arrow style for this test run
BABYBEHAVE_STYLE=arrow ./my_test_binary

# Use tree style
BABYBEHAVE_STYLE=tree ./my_test_binary

# Unset (or set to anything else): defaults to plain
BABYBEHAVE_STYLE=unknown ./my_test_binary  # Uses "plain" (unrecognized values default to plain)

Example (CMake):

add_executable(my_test my_test.cpp)
set_tests_properties(my_test PROPERTIES
    ENVIRONMENT "BABYBEHAVE_STYLE=tree"
)

Note: The SetNarrationStyle() runtime API in bdd.hpp can override this at any point during test execution.

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Summary table

Name	Type	Default	Scope	Purpose
BABYBEHAVE_DISABLE_GHERKIN	Compile-time #define	Not defined (Gherkin ON)	bdd.hpp only	Opt out of Gherkin support for C++17 builds
BABYBEHAVE_NO_SHORT_MACROS	Compile-time #define	Not defined (short macros ON)	bdd.hpp only	Resolve macro name collisions
BABYBEHAVE_QUIET	Environment variable	Unset (narration ON)	All test runs	Silence step narration output
BABYBEHAVE_STYLE	Environment variable	"plain"	All test runs	Select narration style (plain/arrow/tree)