diff --git a/packages/squiggle-lang/__tests__/Distributions/DistributionOperation__test.res b/packages/squiggle-lang/__tests__/Distributions/DistributionOperation__test.res
index d0135cf1..c4410f68 100644
--- a/packages/squiggle-lang/__tests__/Distributions/DistributionOperation__test.res
+++ b/packages/squiggle-lang/__tests__/Distributions/DistributionOperation__test.res
@@ -1,8 +1,5 @@
 open Jest
 open Expect
-open FastCheck
-// open Arbitrary
-open Property.Sync
 
 let env: DistributionOperation.env = {
   sampleCount: 100,
@@ -11,8 +8,6 @@ let env: DistributionOperation.env = {
 
 let mkNormal = (mean, stdev) => GenericDist_Types.Symbolic(#Normal({mean: mean, stdev: stdev}))
 let normalDist5: GenericDist_Types.genericDist = mkNormal(5.0, 2.0)
-let normalDist10: GenericDist_Types.genericDist = mkNormal(10.0, 2.0)
-let normalDist20: GenericDist_Types.genericDist = mkNormal(20.0, 2.0)
 let uniformDist: GenericDist_Types.genericDist = Symbolic(#Uniform({low: 9.0, high: 10.0}))
 
 let {toFloat, toDist, toString, toError} = module(DistributionOperation.Output)
@@ -23,112 +18,6 @@ let outputMap = fmap(~env)
 let toExt: option<'a> => 'a = E.O.toExt(
   "Should be impossible to reach (This error is in test file)",
 )
-let unpackFloat = x => x -> toFloat -> toExt
-
-describe("normalize", () => {
-  test("has no impact on normal dist", () => {
-    let result = run(FromDist(ToDist(Normalize), normalDist5))
-    expect(result)->toEqual(Dist(normalDist5))
-  })
-
-  // Test is vapid while I figure out how to get jest to work with fast-check
-  // monitor situation here maybe https://github.com/TheSpyder/rescript-fast-check/issues/8 ? 
-  test("all normals are already normalized", () => {
-    expect(assert_(
-      property2(
-        Arbitrary.double(()), 
-        Arbitrary.double(()), 
-        (mean, stdev) => { 
-          // open! Expect.Operators
-          open GenericDist_Types.Operation
-          run(FromDist(ToDist(Normalize), mkNormal(mean, stdev))) == DistributionOperation.Dist(mkNormal(mean, stdev))
-        }
-      )
-    )) -> toEqual(())
-  }) 
-})
-
-describe("mean", () => {
-  test("of a normal distribution", () => {  // should be property
-    run(FromDist(ToFloat(#Mean), normalDist5)) -> unpackFloat -> expect -> toBeCloseTo(5.0)
-  })
-
-  test("of an exponential distribution at a small rate", () => {  // should be property 
-    let rate = 1e-7  
-    let theMean = run(FromDist(ToFloat(#Mean), GenericDist_Types.Symbolic(#Exponential({rate: rate}))))
-    theMean -> unpackFloat -> expect -> toBeCloseTo(1.0 /. rate)  // https://en.wikipedia.org/wiki/Exponential_distribution#Mean,_variance,_moments,_and_median
-  })
-
-  test("of an exponential distribution at a larger rate", () => {
-    let rate = 10.0  
-    let theMean = run(FromDist(ToFloat(#Mean), GenericDist_Types.Symbolic(#Exponential({rate: rate}))))
-    theMean -> unpackFloat -> expect -> toBeCloseTo(1.0 /. rate)  // https://en.wikipedia.org/wiki/Exponential_distribution#Mean,_variance,_moments,_and_median
-  })
-
-//  test("of a cauchy distribution", () => {
-//    let result = run(FromDist(ToFloat(#Mean), GenericDist_Types.Symbolic(#Cauchy({local: 1.0, scale: 1.0}))))
-//    expect(result) -> toEqual(Error("Cauchy distributions may have no mean value."))
-//  })
-
-  test("of a triangular distribution", () => {  // should be property
-    let theMean = run(FromDist(
-      ToFloat(#Mean), 
-      GenericDist_Types.Symbolic(#Triangular({low: - 5.0, medium: 1e-3, high: 10.0}))
-    ))
-    theMean -> unpackFloat -> expect -> toBeCloseTo((-5.0 +. 1e-3 +. 10.0) /. 3.0)  // https://www.statology.org/triangular-distribution/
-  })
-
-  test("of a beta distribution with alpha much smaller than beta", () => {  // should be property
-    let theMean = run(FromDist(
-      ToFloat(#Mean), 
-      GenericDist_Types.Symbolic(#Beta({alpha: 2e-4, beta: 64.0}))
-    ))
-    theMean -> unpackFloat -> expect -> toBeCloseTo(1.0 /. (1.0 +. (64.0 /. 2e-4)))  // https://en.wikipedia.org/wiki/Beta_distribution#Mean
-  })
-
-  test("of a beta distribution with alpha much larger than beta", () => {  // should be property
-    let theMean = run(FromDist(
-      ToFloat(#Mean), 
-      GenericDist_Types.Symbolic(#Beta({alpha: 128.0, beta: 1.0}))
-    ))
-    theMean -> unpackFloat -> expect -> toBeCloseTo(1.0 /. (1.0 +. (1.0 /. 128.0)))  // https://en.wikipedia.org/wiki/Beta_distribution#Mean
-  })
-
-  test("of a lognormal", () => {  // should be property
-    let theMean = run(FromDist(
-      ToFloat(#Mean), 
-      GenericDist_Types.Symbolic(#Lognormal({mu: 2.0, sigma: 4.0}))
-    ))
-    theMean -> unpackFloat -> expect -> toBeCloseTo(Js.Math.exp(2.0 +. 4.0 ** 2.0 /. 2.0 ))  // https://brilliant.org/wiki/log-normal-distribution/
-  })
-
-  test("of a uniform", () => {
-    let theMean = run(FromDist(
-      ToFloat(#Mean), 
-      GenericDist_Types.Symbolic(#Uniform({low: 1e-5, high: 12.345}))
-    ))
-    theMean -> unpackFloat -> expect -> toBeCloseTo((1e-5 +. 12.345) /. 2.0)  // https://en.wikipedia.org/wiki/Continuous_uniform_distribution#Moments
-  })
-
-  test("of a float", () => {
-    let theMean = run(FromDist(
-      ToFloat(#Mean), 
-      GenericDist_Types.Symbolic(#Float(7.7))
-    ))
-    theMean -> unpackFloat -> expect -> toBeCloseTo(7.7)
-  })
-})
-
-describe("mixture", () => {
-  test("on two normal distributions", () => {
-    let result =
-      run(Mixture([(normalDist10, 0.5), (normalDist20, 0.5)]))
-      ->outputMap(FromDist(ToFloat(#Mean)))
-      ->toFloat
-      ->toExt
-    expect(result)->toBeCloseTo(15.28)
-  })
-})
 
 describe("toPointSet", () => {
   test("on symbolic normal distribution", () => {
diff --git a/packages/squiggle-lang/__tests__/Distributions/Mixture_test.res b/packages/squiggle-lang/__tests__/Distributions/Mixture_test.res
new file mode 100644
index 00000000..c0cef5a6
--- /dev/null
+++ b/packages/squiggle-lang/__tests__/Distributions/Mixture_test.res
@@ -0,0 +1,57 @@
+open Jest
+open Expect 
+
+let env: DistributionOperation.env = {
+  sampleCount: 1000,
+  xyPointLength: 100,
+}
+
+let {toFloat, toDist, toString, toError} = module(DistributionOperation.Output)
+let {run} = module(DistributionOperation)
+let {fmap} = module(DistributionOperation.Output)
+let run = run(~env)
+let outputMap = fmap(~env)
+let toExt: option<'a> => 'a = E.O.toExt(
+  "Should be impossible to reach (This error is in test file)",
+)
+let unpackFloat = x => x -> toFloat -> toExt
+
+let mkNormal = (mean, stdev) => GenericDist_Types.Symbolic(#Normal({mean: mean, stdev: stdev}))
+let mkBeta = (alpha, beta) => GenericDist_Types.Symbolic(#Beta({alpha: alpha, beta: beta}))
+let mkExponential = rate => GenericDist_Types.Symbolic(#Exponential({rate: rate}))
+
+describe("mixture", () => {
+  testAll("fair mean of two normal distributions", list{(0.0, 1e2), (-1e1, -1e-4), (-1e1, 1e2), (-1e1, 1e1)}, tup => {  // should be property
+    let (mean1, mean2) = tup
+    let theMean = {
+        run(Mixture([(mkNormal(mean1, 9e-1), 0.5), (mkNormal(mean2, 9e-1), 0.5)])) 
+        -> outputMap(FromDist(ToFloat(#Mean)))
+    }
+    theMean -> unpackFloat -> expect -> toBeSoCloseTo((mean1 +. mean2) /. 2.0, ~digits=-1) // the .56 is arbitrary? should be 15.0 with a looser tolerance?
+  })
+  testAll(
+      "weighted mean of a beta and an exponential",
+      // This would not survive property testing, it was easy for me to find cases that NaN'd out. 
+      list{((128.0, 1.0), 2.0), ((2e-1, 64.0), 16.0), ((1e0, 1e0), 64.0)}, 
+      tup => {
+        let (betaParams, rate) = tup
+        let (alpha, beta) = betaParams
+        let theMean = {
+            run(Mixture(
+                [
+                    (mkBeta(alpha, beta), 0.25), 
+                    (mkExponential(rate), 0.75)
+                ]
+            )) -> outputMap(FromDist(ToFloat(#Mean)))
+        }
+        theMean 
+        -> unpackFloat 
+        -> expect 
+        -> toBeSoCloseTo(
+            0.25 *. 1.0 /. (1.0 +. beta /. alpha) +. 0.75 *. 1.0 /. rate, 
+            ~digits=-1
+        )
+      }
+  )
+})
+
diff --git a/packages/squiggle-lang/__tests__/Distributions/Symbolic_test.res b/packages/squiggle-lang/__tests__/Distributions/Symbolic_test.res
new file mode 100644
index 00000000..8e48b3df
--- /dev/null
+++ b/packages/squiggle-lang/__tests__/Distributions/Symbolic_test.res
@@ -0,0 +1,145 @@
+open Jest
+open Expect
+
+let pdfImage = (thePdf, inps) => Js.Array.map(thePdf, inps)
+
+let env: DistributionOperation.env = {
+  sampleCount: 100,
+  xyPointLength: 100,
+}
+
+let mkNormal = (mean, stdev) => GenericDist_Types.Symbolic(#Normal({mean: mean, stdev: stdev}))
+let {toFloat, toDist, toString, toError, fmap} = module(DistributionOperation.Output)
+let {run} = module(DistributionOperation)
+let run = run(~env)
+let outputMap = fmap(~env)
+let toExtFloat: option<float> => float = E.O.toExt(
+  "Should be impossible to reach (This error is in test file)",
+)
+let toExtDist: option<GenericDist_Types.genericDist> => GenericDist_Types.genericDist = E.O.toExt(
+  "Should be impossible to reach (This error is in a test file)", 
+)
+let unpackFloat = x => x -> toFloat -> toExtFloat
+let unpackDist = y => y -> toDist -> toExtDist
+
+describe("normalize", () => {
+  testAll("has no impact on normal distributions", list{-1e8, -16.0, -1e-2, 0.0, 1e-4, 32.0, 1e16}, mean => {
+    let theNormal = mkNormal(mean, 2.0)
+    let theNormalized = run(FromDist(ToDist(Normalize), theNormal))
+    theNormalized 
+    -> unpackDist
+    -> expect
+    -> toEqual(theNormal)
+  })
+})
+
+describe("mean", () => {
+  testAll("of normal distributions", list{-1e8, -16.0, -1e-2, 0.0, 1e-4, 32.0, 1e16}, mean => {
+    run(FromDist(ToFloat(#Mean), mkNormal(mean, 4.0))) 
+    -> unpackFloat 
+    -> expect 
+    -> toBeCloseTo(mean)
+  })
+
+  testAll("of exponential distributions", list{1e-7, 2.0, 10.0, 100.0}, rate => {
+    let theMean = run(FromDist(ToFloat(#Mean), GenericDist_Types.Symbolic(#Exponential({rate: rate}))))
+    theMean -> unpackFloat -> expect -> toBeCloseTo(1.0 /. rate)  // https://en.wikipedia.org/wiki/Exponential_distribution#Mean,_variance,_moments,_and_median
+  })
+
+//  test("of a cauchy distribution", () => {
+//    let result = run(FromDist(ToFloat(#Mean), GenericDist_Types.Symbolic(#Cauchy({local: 1.0, scale: 1.0}))))
+//    expect(result) -> toEqual(Error("Cauchy distributions may have no mean value."))
+//  })
+
+  test("of a triangular distribution", () => {  // should be property
+    let theMean = run(FromDist(
+      ToFloat(#Mean), 
+      GenericDist_Types.Symbolic(#Triangular({low: - 5.0, medium: 1e-3, high: 10.0}))
+    ))
+    theMean 
+    -> unpackFloat 
+    -> expect 
+    -> toBeCloseTo((-5.0 +. 1e-3 +. 10.0) /. 3.0)  // https://www.statology.org/triangular-distribution/
+  })
+
+  test("of a beta distribution with alpha much smaller than beta", () => {  // should be property
+    let theMean = run(FromDist(
+      ToFloat(#Mean), 
+      GenericDist_Types.Symbolic(#Beta({alpha: 2e-4, beta: 64.0}))
+    ))
+    theMean 
+    -> unpackFloat 
+    -> expect 
+    -> toBeCloseTo(1.0 /. (1.0 +. (64.0 /. 2e-4)))  // https://en.wikipedia.org/wiki/Beta_distribution#Mean
+  })
+
+  test("of a beta distribution with alpha much larger than beta", () => {  // should be property
+    let theMean = run(FromDist(
+      ToFloat(#Mean), 
+      GenericDist_Types.Symbolic(#Beta({alpha: 128.0, beta: 1.0}))
+    ))
+    theMean 
+    -> unpackFloat 
+    -> expect 
+    -> toBeCloseTo(1.0 /. (1.0 +. (1.0 /. 128.0)))  // https://en.wikipedia.org/wiki/Beta_distribution#Mean
+  })
+
+  test("of a lognormal", () => {  // should be property
+    let theMean = run(FromDist(
+      ToFloat(#Mean), 
+      GenericDist_Types.Symbolic(#Lognormal({mu: 2.0, sigma: 4.0}))
+    ))
+    theMean 
+    -> unpackFloat 
+    -> expect 
+    -> toBeCloseTo(Js.Math.exp(2.0 +. 4.0 ** 2.0 /. 2.0 ))  // https://brilliant.org/wiki/log-normal-distribution/
+  })
+
+  test("of a uniform", () => {
+    let theMean = run(FromDist(
+      ToFloat(#Mean), 
+      GenericDist_Types.Symbolic(#Uniform({low: 1e-5, high: 12.345}))
+    ))
+    theMean 
+    -> unpackFloat 
+    -> expect 
+    -> toBeCloseTo((1e-5 +. 12.345) /. 2.0)  // https://en.wikipedia.org/wiki/Continuous_uniform_distribution#Moments
+  })
+
+  test("of a float", () => {
+    let theMean = run(FromDist(
+      ToFloat(#Mean), 
+      GenericDist_Types.Symbolic(#Float(7.7))
+    ))
+    theMean -> unpackFloat -> expect -> toBeCloseTo(7.7)
+  })
+})
+
+describe("Normal distribution with sparklines", () => {
+
+  let parameterWiseAdditionHelper = (n1: SymbolicDistTypes.normal, n2: SymbolicDistTypes.normal) => {
+    let normalDistAtSumMeanConstr = SymbolicDist.Normal.add(n1, n2)
+    let normalDistAtSumMean: SymbolicDistTypes.normal = switch normalDistAtSumMeanConstr {
+      | #Normal(params) => params
+    }
+    x => SymbolicDist.Normal.pdf(x, normalDistAtSumMean)
+  }
+
+  let normalDistAtMean5: SymbolicDistTypes.normal = {mean: 5.0, stdev: 2.0}
+  let normalDistAtMean10: SymbolicDistTypes.normal = {mean: 10.0, stdev: 2.0}
+  let range20Float = E.A.rangeFloat(0, 20) // [0.0,1.0,2.0,3.0,4.0,...19.0,]
+
+  let pdfNormalDistAtMean5 = x => SymbolicDist.Normal.pdf(x, normalDistAtMean5)
+  let sparklineMean5 = pdfImage(pdfNormalDistAtMean5, range20Float)
+  test("mean=5", () => {
+    Sparklines.create(sparklineMean5, ()) 
+    -> expect 
+    -> toEqual(`▁▂▃▅███▅▃▂▁▁▁▁▁▁▁▁▁▁▁`)
+  })
+  let sparklineMean15 = normalDistAtMean5 -> parameterWiseAdditionHelper(normalDistAtMean10) -> pdfImage(range20Float)
+  test("parameter-wise addition of two normal distributions", () => {
+    Sparklines.create(sparklineMean15, ())
+    -> expect
+    -> toEqual(`▁▁▁▁▁▁▁▁▁▁▂▃▅▇███▇▅▃▂`)
+  })
+})
diff --git a/packages/squiggle-lang/__tests__/Symbolic_test.res b/packages/squiggle-lang/__tests__/Symbolic_test.res
deleted file mode 100644
index 8ec3be22..00000000
--- a/packages/squiggle-lang/__tests__/Symbolic_test.res
+++ /dev/null
@@ -1,33 +0,0 @@
-open Jest
-open Expect
-open Js.Array
-open SymbolicDist
-
-let makeTest = (~only=false, str, item1, item2) =>
-  only
-    ? Only.test(str, () => expect(item1) -> toEqual(item2))
-    : test(str, () => expect(item1) -> toEqual(item2))
-
-let pdfImage = (thePdf, inps) => map(thePdf, inps)
-
-let parameterWiseAdditionHelper = (n1: SymbolicDistTypes.normal, n2: SymbolicDistTypes.normal) => {
-  let normalDistAtSumMeanConstr = Normal.add(n1, n2)
-  let normalDistAtSumMean: SymbolicDistTypes.normal = switch normalDistAtSumMeanConstr {
-    | #Normal(params) => params
-  }
-  x => Normal.pdf(x, normalDistAtSumMean)
-}
-
-describe("Normal distribution with sparklines", () => {
-
-  let normalDistAtMean5: SymbolicDistTypes.normal = {mean: 5.0, stdev: 2.0}
-  let normalDistAtMean10: SymbolicDistTypes.normal = {mean: 10.0, stdev: 2.0}
-  let range20Float = E.A.rangeFloat(0, 20) // [0.0,1.0,2.0,3.0,4.0,...19.0,]
-
-  let pdfNormalDistAtMean5 = x => Normal.pdf(x, normalDistAtMean5)
-  let sparklineMean5 = pdfImage(pdfNormalDistAtMean5, range20Float)
-  makeTest("mean=5", Sparklines.create(sparklineMean5, ()), `▁▂▃▅███▅▃▂▁▁▁▁▁▁▁▁▁▁▁`)
-
-  let sparklineMean15 = normalDistAtMean5 -> parameterWiseAdditionHelper(normalDistAtMean10) -> pdfImage(range20Float)
-  makeTest("parameter-wise addition of two normal distributions", Sparklines.create(sparklineMean15, ()), `▁▁▁▁▁▁▁▁▁▁▂▃▅▇███▇▅▃▂`)
-})