diff --git a/Sources/PressureEstimationsFeature/EquipmentMeasurementForm.swift b/Sources/PressureEstimationsFeature/EquipmentMeasurementForm.swift
index b990881..2aca088 100644
--- a/Sources/PressureEstimationsFeature/EquipmentMeasurementForm.swift
+++ b/Sources/PressureEstimationsFeature/EquipmentMeasurementForm.swift
@@ -9,14 +9,14 @@ public struct EquipmentMeasurementForm {
   
   public init() { }
   
-  @Reducer(state: .equatable)
+  @Reducer(state: .equatable, .sendable, action: .sendable)
   public enum Destination {
     case flaggedMeasurementsList(FlaggedMeasurementsList)
     case infoView(InfoViewFeature)
   }
   
   @ObservableState
-  public struct State: Equatable {
+  public struct State: Equatable, Sendable {
     @Presents public var destination: Destination.State?
     @Shared public var sharedSettings: SharedPressureEstimationSettings
     public var allowEquipmentTypeSelection: Bool
@@ -65,7 +65,7 @@ public struct EquipmentMeasurementForm {
       }
     }
     
-    public struct Measurements: Equatable {
+    public struct Measurements: Equatable, Sendable {
       public var airflow: Double?
       public var returnPlenumPressure: Double?
       public var postFilterPressure: Double?
@@ -136,7 +136,7 @@ public struct EquipmentMeasurementForm {
       }
     }
     
-    public enum Field: CaseIterable, FocusableField, Hashable, Identifiable {
+    public enum Field: CaseIterable, FocusableField, Hashable, Identifiable, Sendable {
       case returnPlenumPressure
       case postFilterPressure
       case coilPressure
@@ -148,13 +148,13 @@ public struct EquipmentMeasurementForm {
     }
   }
   
-  public enum Action: BindableAction, ViewAction {
+  public enum Action: BindableAction, ViewAction, Sendable {
     case binding(BindingAction<State>)
     case destination(PresentationAction<Destination.Action>)
     case view(View)
     
     @CasePathable
-    public enum View {
+    public enum View: Sendable {
       case infoButtonTapped
       case nextButtonTapped
       case onAppear
diff --git a/Tests/EstimatedPressureTests/EstimatedPressureTests.swift b/Tests/EstimatedPressureTests/EstimatedPressureTests.swift
index ce8b1bd..c7447d3 100644
--- a/Tests/EstimatedPressureTests/EstimatedPressureTests.swift
+++ b/Tests/EstimatedPressureTests/EstimatedPressureTests.swift
@@ -2,6 +2,7 @@ import Dependencies
 import EstimatedPressureDependency
 import SharedModels
 import XCTest
+import Testing
 
 final class PositiveNumericTests: XCTestCase {
 
@@ -40,6 +41,8 @@ final class PositiveNumericTests: XCTestCase {
   func testExternalStaticPressure() {
     var envelope = EquipmentMeasurement.furnaceAndCoil(
       .init(
+        airflow: 1200,
+        manufacturersIncludedFilterPressureDrop: 0,
         returnPlenumPressure: -0.1,
         postFilterPressure: -0.2, // here to test it makes positive.
         preCoilPressure: 0.4,
@@ -47,48 +50,47 @@ final class PositiveNumericTests: XCTestCase {
       )
     )
 
-    var sut = envelope.externalStaticPressure
+    var sut = envelope.externalStaticPressure.positiveValue
     XCTAssertEqual(round(sut * 10) / 10, 0.6)
 
 
     envelope = .airHandler(
       .init(
+        airflow: 1200,
+        manufacturersIncludedFilterPressureDrop: 0,
         returnPlenumPressure: -0.2,
         postFilterPressure: 0.3,
         postCoilPressure: 0.5,
         supplyPlenumPressure: 0.3)
     )
 
-    sut = envelope.externalStaticPressure
+    sut = envelope.externalStaticPressure.positiveValue
     XCTAssertEqual(round(sut * 10) / 10, 0.7)
 
   }
 
-  func testExternalStaticPressureReturnsZero() {
-    XCTAssertEqual(
-      EquipmentMeasurement.airHandler(.init()).externalStaticPressure,
-      0
-    )
-    XCTAssertEqual(
-      EquipmentMeasurement.furnaceAndCoil(.init()).externalStaticPressure,
-      0
-    )
+  @Test(
+    "Values are positive only",
+    arguments: [
+      0.1,
+      -0.1
+    ]
+  )
+  func valuesArePositiveOnly(value: Double) {
+    let positive = Positive<Double>(value)
+    #expect(positive.positiveValue == 0.1)
   }
 
-  func testValuesArePositiveOnly() {
-    let sut = Positive<Double>(wrappedValue: -0.1)
-    XCTAssertEqual(sut.positiveValue, 0.1)
-
-    let sut2 = Positive<Double?>(wrappedValue: -0.1)
-    XCTAssertEqual(sut2.positiveValue, 0.1)
+  @Test(
+    "PlenumDimension area calculation",
+    arguments: [
+      (PlenumDimension.rectangular(width: 24, height: 12), 2),
+      (PlenumDimension.round(16), 1.4)
+    ]
+  )
+  func plenumDimensionArea(dimension: PlenumDimension, expectation: Double) {
+    let sut = round(dimension.areaInSquareFeet * 100) / 100
+    #expect(sut == expectation)
   }
 
-  func testReturnPlenumDimensionsAreaCalculation() {
-    var sut = PlenumDimension.rectangular(width: 24, height: 12)
-    XCTAssertEqual(sut.areaInSquareFeet, 2)
-
-    sut = .round(16)
-    XCTAssertEqual(round(sut.areaInSquareFeet * 100) / 100, 1.4)
-
-  }
 }
diff --git a/Tests/EstimatedPressureTests/PercentageTests.swift b/Tests/EstimatedPressureTests/PercentageTests.swift
index 6a7aebd..838ea0a 100644
--- a/Tests/EstimatedPressureTests/PercentageTests.swift
+++ b/Tests/EstimatedPressureTests/PercentageTests.swift
@@ -1,62 +1,72 @@
 import SharedModels
+import Testing
 import XCTest
 
-final class PercentageTests: XCTestCase {
+struct PercentagePostfixOperatorTests {
+  static let arguments: [(Percentage, Double)] = [
+    (50%, 50),
+    (50.01%, 50.01),
+    (110%, 110)
+  ]
 
-  func testPostfixOperator() {
-    var sut = 50%
-    XCTAssertEqual(sut.rawValue, 50)
-
-    sut = 50.01%
-    XCTAssertEqual(sut.rawValue, 50.01)
-  }
-
-  func testFractionInitialization() {
-    let sut = Percentage(fraction: 0.5)
-    XCTAssertEqual(sut.rawValue, 50)
-    XCTAssertEqual(sut.fraction, 0.5)
-  }
-
-  func testExpressibleByFloatLiteral() {
-    let sut: Percentage = 50.01
-    XCTAssertEqual(sut.rawValue, 50.01)
-  }
-
-  func testExpressibleByIntegerLiteral() {
-    let sut: Percentage = 50
-    XCTAssertEqual(sut.rawValue, 50)
-  }
-
-  func testMultiplication() {
-    var sut = 2% * 25%
-    XCTAssertEqual(sut, 50%)
-
-    sut *= 2
-    XCTAssertEqual(sut, 100%)
-  }
-
-  func testAddition() {
-    var sut = 35% + 15%
-    XCTAssertEqual(sut, 50%)
-
-    sut += 25%
-    XCTAssertEqual(sut, 75%)
-  }
-
-  func testSubtraction() {
-    let sut = 50% - 15%
-    XCTAssertEqual(sut, 35%)
-  }
-
-  func testComparable() {
-    let sut1 = 50%
-    let sut2 = 35%
-
-    XCTAssert(sut2 < sut1)
-  }
-
-  func testCustomStringConvertible() {
-    let sut = 50%
-    XCTAssertEqual(sut.description, "50%")
+  @Test("Percentage Postfix Operator", arguments: Self.arguments)
+  func postfixTest(percentage: Percentage, expectation: Double) {
+    #expect(percentage.rawValue == expectation)
   }
 }
+
+struct PercentageInitializationTests {
+
+  @Test("Percentage expressible tests")
+  func percentageExpressible(){
+    let intLiteral: Percentage = 50
+    #expect(intLiteral.rawValue == 50)
+
+    let floatLiteral: Percentage = 50.01
+    #expect(floatLiteral.rawValue == 50.01)
+  }
+
+  @Test("Fraction initialization")
+  func fraction() {
+    let sut = Percentage(fraction: 0.5)
+    #expect(sut.rawValue == 50)
+    #expect(sut.fraction == 0.5)
+  }
+}
+
+struct PercentageMathTests {
+
+  let first = 2%
+  let second = 25%
+
+  @Test("Percentage addition")
+  func addition() {
+    let sut = first + second
+    #expect(sut == 27%)
+  }
+
+  @Test("Percentage subtraction")
+  func subtraction() {
+    let sut = second - first
+    #expect(sut == 23%)
+  }
+
+  @Test("Percentage multiplication")
+  func multiplication() {
+    let sut = first * second
+    #expect(sut == 50%)
+  }
+
+  @Test("Percentage comparable")
+  func comparable() {
+    #expect(first < second)
+    #expect(second > first)
+    #expect(first >= first)
+    #expect(second <= second)
+  }
+}
+
+@Test("Percentage custom string convertible")
+func percentageString() {
+  #expect(50%.description == "50%")
+}