diff --git a/src/features/conversion.ts b/src/features/conversion.ts
index 1ccf26b..a184de0 100644
--- a/src/features/conversion.ts
+++ b/src/features/conversion.ts
@@ -133,11 +133,11 @@ export function createConversion<T extends ConversionOptions>(
         );
         if (conversion.currentGain == null) {
             conversion.currentGain = computed(() => {
-                let gain = (conversion as GenericConversion).formula.evaluate(
-                    conversion.baseResource.value
-                );
-                gain = Decimal.floor(gain).max(0);
-
+                let gain = Decimal.floor(
+                    (conversion as GenericConversion).formula.evaluate(
+                        conversion.baseResource.value
+                    )
+                ).max(0);
                 if (unref(conversion.buyMax) === false) {
                     gain = gain.min(1);
                 }
@@ -218,10 +218,11 @@ export function createIndependentConversion<S extends ConversionOptions>(
 
         if (conversion.currentGain == null) {
             conversion.currentGain = computed(() => {
-                let gain = (conversion as unknown as GenericConversion).formula.evaluate(
-                    conversion.baseResource.value
-                );
-                gain = Decimal.floor(gain).max(conversion.gainResource.value);
+                let gain = Decimal.floor(
+                    (conversion as unknown as GenericConversion).formula.evaluate(
+                        conversion.baseResource.value
+                    )
+                ).max(conversion.gainResource.value);
                 if (unref(conversion.buyMax) === false) {
                     gain = gain.min(Decimal.add(conversion.gainResource.value, 1));
                 }
@@ -235,7 +236,9 @@ export function createIndependentConversion<S extends ConversionOptions>(
                         conversion.baseResource.value
                     ),
                     conversion.gainResource.value
-                ).max(0);
+                )
+                    .floor()
+                    .max(0);
 
                 if (unref(conversion.buyMax) === false) {
                     gain = gain.min(1);
@@ -263,13 +266,13 @@ export function createIndependentConversion<S extends ConversionOptions>(
  * @param layer The layer this passive generation will be associated with. Typically `this` when calling this function from inside a layer's options function.
  * @param conversion The conversion that will determine how much generation there is.
  * @param rate A multiplier to multiply against the conversion's currentGain.
- * @param cap A value that should not be passed via passive generation. If null, no cap is applied.
+ * @param cap A value that should not be passed via passive generation.
  */
 export function setupPassiveGeneration(
     layer: BaseLayer,
     conversion: GenericConversion,
     rate: Computable<DecimalSource> = 1,
-    cap: Computable<DecimalSource | null> = null
+    cap: Computable<DecimalSource> = Decimal.dInf
 ): void {
     const processedRate = convertComputable(rate);
     const processedCap = convertComputable(cap);
@@ -280,7 +283,7 @@ export function setupPassiveGeneration(
                 conversion.gainResource.value,
                 Decimal.times(currRate, diff).times(Decimal.ceil(unref(conversion.actualGain)))
             )
-                .min(unref(processedCap) ?? Decimal.dInf)
+                .min(unref(processedCap))
                 .max(conversion.gainResource.value);
         }
     });
diff --git a/tests/features/conversions.test.ts b/tests/features/conversions.test.ts
new file mode 100644
index 0000000..fc1d68d
--- /dev/null
+++ b/tests/features/conversions.test.ts
@@ -0,0 +1,502 @@
+import {
+    createCumulativeConversion,
+    createIndependentConversion,
+    GenericConversion,
+    setupPassiveGeneration
+} from "features/conversion";
+import { createResource, Resource } from "features/resources/resource";
+import { GenericFormula } from "game/formulas/types";
+import { createLayer } from "game/layers";
+import Decimal from "util/bignum";
+import { afterAll, afterEach, beforeAll, beforeEach, describe, expect, test, vi } from "vitest";
+import { ref, unref } from "vue";
+import "../utils";
+
+describe("Creating conversion", () => {
+    let baseResource: Resource;
+    let gainResource: Resource;
+    let formula: (x: GenericFormula) => GenericFormula;
+    beforeEach(() => {
+        baseResource = createResource(ref(40));
+        gainResource = createResource(ref(1));
+        formula = x => x.div(10).sqrt();
+    });
+    afterEach(() => {
+        vi.restoreAllMocks();
+    });
+
+    describe("Cumulative conversion", () => {
+        describe("Calculates currentGain correctly", () => {
+            let conversion: GenericConversion;
+            beforeEach(() => {
+                conversion = createCumulativeConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula
+                }));
+            });
+            test("Exactly enough", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10);
+                expect(unref(conversion.currentGain)).compare_tolerance(100);
+            });
+            test("Just under", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).sub(1);
+                expect(unref(conversion.currentGain)).compare_tolerance(99);
+            });
+            test("Just over", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).add(1);
+                expect(unref(conversion.currentGain)).compare_tolerance(100);
+            });
+        });
+        describe("Calculates actualGain correctly", () => {
+            let conversion: GenericConversion;
+            beforeEach(() => {
+                conversion = createCumulativeConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula
+                }));
+            });
+            test("Exactly enough", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10);
+                expect(unref(conversion.actualGain)).compare_tolerance(100);
+            });
+            test("Just under", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).sub(1);
+                expect(unref(conversion.actualGain)).compare_tolerance(99);
+            });
+            test("Just over", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).add(1);
+                expect(unref(conversion.actualGain)).compare_tolerance(100);
+            });
+        });
+        describe("Calculates currentAt correctly", () => {
+            let conversion: GenericConversion;
+            beforeEach(() => {
+                conversion = createCumulativeConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula
+                }));
+            });
+            test("Exactly enough", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10);
+                expect(unref(conversion.currentAt)).compare_tolerance(
+                    Decimal.pow(100, 2).times(10)
+                );
+            });
+            test("Just under", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).sub(1);
+                expect(unref(conversion.currentAt)).compare_tolerance(Decimal.pow(99, 2).times(10));
+            });
+            test("Just over", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).add(1);
+                expect(unref(conversion.currentAt)).compare_tolerance(
+                    Decimal.pow(100, 2).times(10)
+                );
+            });
+        });
+        describe("Calculates nextAt correctly", () => {
+            let conversion: GenericConversion;
+            beforeEach(() => {
+                conversion = createCumulativeConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula
+                }));
+            });
+            test("Exactly enough", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10);
+                expect(unref(conversion.nextAt)).compare_tolerance(Decimal.pow(101, 2).times(10));
+            });
+            test("Just under", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).sub(1);
+                expect(unref(conversion.nextAt)).compare_tolerance(Decimal.pow(100, 2).times(10));
+            });
+            test("Just over", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).add(1);
+                expect(unref(conversion.nextAt)).compare_tolerance(Decimal.pow(101, 2).times(10));
+            });
+        });
+        test("Converts correctly", () => {
+            const conversion = createCumulativeConversion(() => ({
+                baseResource,
+                gainResource,
+                formula
+            }));
+            conversion.convert();
+            expect(baseResource.value).compare_tolerance(0);
+            expect(gainResource.value).compare_tolerance(3);
+        });
+        describe("Obeys buy max", () => {
+            test("buyMax = false", () => {
+                const conversion = createCumulativeConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula,
+                    buyMax: false
+                }));
+                expect(unref(conversion.actualGain)).compare_tolerance(1);
+            });
+            test("buyMax = true", () => {
+                const conversion = createCumulativeConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula,
+                    buyMax: true
+                }));
+                expect(unref(conversion.actualGain)).compare_tolerance(2);
+            });
+        });
+        test("Spends correctly", () => {
+            const conversion = createCumulativeConversion(() => ({
+                baseResource,
+                gainResource,
+                formula
+            }));
+            conversion.convert();
+            expect(baseResource.value).compare_tolerance(0);
+        });
+        test("Calls onConvert", () => {
+            const onConvert = vi.fn();
+            const conversion = createCumulativeConversion(() => ({
+                baseResource,
+                gainResource,
+                formula,
+                onConvert
+            }));
+            conversion.convert();
+            expect(onConvert).toHaveBeenCalled();
+        });
+    });
+
+    describe("Independent conversion", () => {
+        describe("Calculates currentGain correctly", () => {
+            let conversion: GenericConversion;
+            beforeEach(() => {
+                conversion = createIndependentConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula,
+                    buyMax: true
+                }));
+            });
+            test("Exactly enough", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10);
+                expect(unref(conversion.currentGain)).compare_tolerance(100);
+            });
+            test("Just under", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).sub(1);
+                expect(unref(conversion.currentGain)).compare_tolerance(99);
+            });
+            test("Just over", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).add(1);
+                expect(unref(conversion.currentGain)).compare_tolerance(100);
+            });
+        });
+        describe("Calculates actualGain correctly", () => {
+            let conversion: GenericConversion;
+            beforeEach(() => {
+                conversion = createIndependentConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula,
+                    buyMax: true
+                }));
+            });
+            test("Exactly enough", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10);
+                expect(unref(conversion.actualGain)).compare_tolerance(99);
+            });
+            test("Just under", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).sub(1);
+                expect(unref(conversion.actualGain)).compare_tolerance(98);
+            });
+            test("Just over", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).add(1);
+                expect(unref(conversion.actualGain)).compare_tolerance(99);
+            });
+        });
+        describe("Calculates currentAt correctly", () => {
+            let conversion: GenericConversion;
+            beforeEach(() => {
+                conversion = createIndependentConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula,
+                    buyMax: true
+                }));
+            });
+            test("Exactly enough", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10);
+                expect(unref(conversion.currentAt)).compare_tolerance(
+                    Decimal.pow(100, 2).times(10)
+                );
+            });
+            test("Just under", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).sub(1);
+                expect(unref(conversion.currentAt)).compare_tolerance(Decimal.pow(99, 2).times(10));
+            });
+            test("Just over", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).add(1);
+                expect(unref(conversion.currentAt)).compare_tolerance(
+                    Decimal.pow(100, 2).times(10)
+                );
+            });
+        });
+        describe("Calculates nextAt correctly", () => {
+            let conversion: GenericConversion;
+            beforeEach(() => {
+                conversion = createIndependentConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula,
+                    buyMax: true
+                }));
+            });
+            test("Exactly enough", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10);
+                expect(unref(conversion.nextAt)).compare_tolerance(Decimal.pow(101, 2).times(10));
+            });
+            test("Just under", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).sub(1);
+                expect(unref(conversion.nextAt)).compare_tolerance(Decimal.pow(100, 2).times(10));
+            });
+            test("Just over", () => {
+                baseResource.value = Decimal.pow(100, 2).times(10).add(1);
+                expect(unref(conversion.nextAt)).compare_tolerance(Decimal.pow(101, 2).times(10));
+            });
+        });
+        test("Converts correctly", () => {
+            const conversion = createIndependentConversion(() => ({
+                baseResource,
+                gainResource,
+                formula
+            }));
+            conversion.convert();
+            expect(baseResource.value).compare_tolerance(0);
+            expect(gainResource.value).compare_tolerance(2);
+        });
+        describe("Obeys buy max", () => {
+            test("buyMax = false", () => {
+                const conversion = createIndependentConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula,
+                    buyMax: false
+                }));
+                baseResource.value = 90;
+                expect(unref(conversion.actualGain)).compare_tolerance(1);
+            });
+            test("buyMax = true", () => {
+                const conversion = createIndependentConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula,
+                    buyMax: true
+                }));
+                baseResource.value = 90;
+                expect(unref(conversion.actualGain)).compare_tolerance(2);
+            });
+        });
+        test("Spends correctly", () => {
+            const conversion = createIndependentConversion(() => ({
+                baseResource,
+                gainResource,
+                formula
+            }));
+            conversion.convert();
+            expect(baseResource.value).compare_tolerance(0);
+        });
+        test("Calls onConvert", () => {
+            const onConvert = vi.fn();
+            const conversion = createIndependentConversion(() => ({
+                baseResource,
+                gainResource,
+                formula,
+                onConvert
+            }));
+            conversion.convert();
+            expect(onConvert).toHaveBeenCalled();
+        });
+    });
+    describe("Custom conversion", () => {
+        describe("Custom cumulative", () => {
+            let conversion: GenericConversion;
+            const convert = vi.fn();
+            const spend = vi.fn();
+            const onConvert = vi.fn();
+            beforeAll(() => {
+                conversion = createCumulativeConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula,
+                    currentGain() {
+                        return 10;
+                    },
+                    actualGain() {
+                        return 5;
+                    },
+                    currentAt() {
+                        return 100;
+                    },
+                    nextAt() {
+                        return 1000;
+                    },
+                    convert,
+                    spend,
+                    onConvert
+                }));
+            });
+            afterEach(() => {
+                vi.resetAllMocks();
+            });
+            test("Calculates currentGain correctly", () => {
+                expect(unref(conversion.currentGain)).compare_tolerance(10);
+            });
+            test("Calculates actualGain correctly", () => {
+                expect(unref(conversion.actualGain)).compare_tolerance(5);
+            });
+            test("Calculates currentAt correctly", () => {
+                expect(unref(conversion.currentAt)).compare_tolerance(100);
+            });
+            test("Calculates nextAt correctly", () => {
+                expect(unref(conversion.nextAt)).compare_tolerance(1000);
+            });
+            test("Calls convert", () => {
+                conversion.convert();
+                expect(convert).toHaveBeenCalled();
+            });
+            test("Calls spend and onConvert", () => {
+                conversion = createCumulativeConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula,
+                    spend,
+                    onConvert
+                }));
+                conversion.convert();
+                expect(spend).toHaveBeenCalled();
+                expect(spend).toHaveBeenCalledWith(expect.compare_tolerance(2));
+                expect(onConvert).toHaveBeenCalled();
+                expect(onConvert).toHaveBeenCalledWith(expect.compare_tolerance(2));
+            });
+        });
+        describe("Custom independent", () => {
+            let conversion: GenericConversion;
+            const convert = vi.fn();
+            const spend = vi.fn();
+            const onConvert = vi.fn();
+            beforeAll(() => {
+                conversion = createIndependentConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula,
+                    currentGain() {
+                        return 10;
+                    },
+                    actualGain() {
+                        return 5;
+                    },
+                    currentAt() {
+                        return 100;
+                    },
+                    nextAt() {
+                        return 1000;
+                    },
+                    convert,
+                    spend,
+                    onConvert
+                }));
+            });
+            afterEach(() => {
+                vi.resetAllMocks();
+            });
+            test("Calculates currentGain correctly", () => {
+                expect(unref(conversion.currentGain)).compare_tolerance(10);
+            });
+            test("Calculates actualGain correctly", () => {
+                expect(unref(conversion.actualGain)).compare_tolerance(5);
+            });
+            test("Calculates currentAt correctly", () => {
+                expect(unref(conversion.currentAt)).compare_tolerance(100);
+            });
+            test("Calculates nextAt correctly", () => {
+                expect(unref(conversion.nextAt)).compare_tolerance(1000);
+            });
+            test("Calls convert", () => {
+                conversion.convert();
+                expect(convert).toHaveBeenCalled();
+            });
+            test("Calls spend and onConvert", () => {
+                conversion = createIndependentConversion(() => ({
+                    baseResource,
+                    gainResource,
+                    formula,
+                    spend,
+                    onConvert
+                }));
+                conversion.convert();
+                expect(spend).toHaveBeenCalled();
+                expect(spend).toHaveBeenCalledWith(expect.compare_tolerance(1));
+                expect(onConvert).toHaveBeenCalled();
+                expect(onConvert).toHaveBeenCalledWith(expect.compare_tolerance(1));
+            });
+        });
+    });
+});
+
+describe("Passive generation", () => {
+    let baseResource: Resource;
+    let gainResource: Resource;
+    let formula: (x: GenericFormula) => GenericFormula;
+    beforeEach(() => {
+        baseResource = createResource(ref(40));
+        gainResource = createResource(ref(1));
+        formula = x => x.div(10).sqrt();
+    });
+    test("Rate is 0", () => {
+        const conversion = createCumulativeConversion(() => ({
+            baseResource,
+            gainResource,
+            formula
+        }));
+        const layer = createLayer("dummy", () => ({ display: "" }));
+        setupPassiveGeneration(layer, conversion, 0);
+        layer.emit("preUpdate", 100);
+        expect(gainResource.value).compare_tolerance(1);
+    });
+    test("Rate is 1", () => {
+        const conversion = createCumulativeConversion(() => ({
+            baseResource,
+            gainResource,
+            formula
+        }));
+        const layer = createLayer("dummy", () => ({ display: "" }));
+        setupPassiveGeneration(layer, conversion);
+        layer.emit("preUpdate", 100);
+        expect(gainResource.value).compare_tolerance(201);
+    })
+    test("Rate is 100", () => {
+        const conversion = createCumulativeConversion(() => ({
+            baseResource,
+            gainResource,
+            formula
+        }));
+        const layer = createLayer("dummy", () => ({ display: "" }));
+        setupPassiveGeneration(layer, conversion, () => 100);
+        layer.emit("preUpdate", 100);
+        expect(gainResource.value).compare_tolerance(20001);
+    })
+    test("Obeys cap", () => {
+        const conversion = createCumulativeConversion(() => ({
+            baseResource,
+            gainResource,
+            formula
+        }));
+        const layer = createLayer("dummy", () => ({ display: "" }));
+        setupPassiveGeneration(layer, conversion, 100, () => 100);
+        layer.emit("preUpdate", 100);
+        expect(gainResource.value).compare_tolerance(100);
+    })
+});