ChiselScalatestTester

chiseltest.ChiselScalatestTester

ChiselTest-compatible API that delegates to ChiselSim (Chisel 7)

This trait provides the ChiselTest API that users are familiar with from Chisel 6, but internally uses ChiselSim from Chisel 7 to perform the actual testing.

VCD GENERATION SUPPORT: This compatibility layer supports VCD generation when WriteVcdAnnotation is used. VCD files are generated in: build/chiselsim/ /workdir-verilator/trace.vcd

AUTOMATIC RESET FEATURE: By default, this trait automatically resets the module before running tests, mimicking ChiselTest's behavior from Chisel 6.

To disable auto-reset or customize the reset duration:

class MyTest extends AnyFlatSpec with ChiselScalatestTester {
 override def autoResetEnabled: Boolean = false  // Disable auto-reset
 override def resetCycles: Int = 5               // Or change duration
}

Example usage with VCD:

import chiseltest._
import org.scalatest.flatspec.AnyFlatSpec

class MyModuleSpec extends AnyFlatSpec with ChiselScalatestTester {
 behavior of "MyModule"

 it should "generate waveforms" in {
   test(new MyModule).withAnnotations(Seq(WriteVcdAnnotation)) { dut =>
     dut.io.in.poke(42.U)
     dut.clock.step()
     dut.io.out.expect(42.U)
   }
   // VCD file: build/chiselsim/<timestamp>/workdir-verilator/trace.vcd
 }
}

Attributes

Source: ChiselScalatestTester.scala
Graph
Supertypes: class Object

trait Matchable

class Any

Members list

Type members

Classlikes

Builder class to support .withAnnotations() chaining

Value parameters

autoReset: Whether automatic reset is enabled
dutGen: Generator for the device under test
resetCyc: Number of reset cycles to apply

Attributes

Source: ChiselScalatestTester.scala
Supertypes: class Object

trait Matchable

class Any

Runner class that executes the test with VCD support

Value parameters

annotations: Annotation list used to configure execution behavior
autoReset: Whether automatic reset is enabled
dutGen: Generator for the device under test
resetCyc: Number of reset cycles to apply

Attributes

Source: ChiselScalatestTester.scala
Supertypes: class Object

trait Matchable

class Any

Value members

Concrete methods

Enable automatic reset before each test. Override this to disable auto-reset if needed.

Attributes

Source: ChiselScalatestTester.scala

Number of clock cycles to assert reset. Override this to change reset duration.

Attributes

Source: ChiselScalatestTester.scala

Test a module with the given stimulus

This method provides the ChiselTest interface.

Type parameters

T: The type of module being tested

Value parameters

dutGen: A generator function that creates the device under test

Attributes

Source: ChiselScalatestTester.scala

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