added a test and corrections to docs

Author: tungli

src/findpeaks.jl

@@ -35,8 +35,12 @@ end
 x::Array{S}=collect(1:length(y))
 ;min_height::T=minimum(y), min_prom::T=minimum(y),
 min_dist::S=0, threshold::T=0 ) where {T<:Real,S}`\n
-Returns indices of local maxima (sorted from highest peaks to lowest)
-in 1D array of real numbers. Similar to MATLAB's findpeaks().\n
+
+Finds peaks in 1D array. Similar to MATLAB's findpeaks().\n
+Returns:\n
+* tuple of peak positions found
+* a tuple of `PeakInfo` structures with additional information about peaks.
+
 *Arguments*:\n
 `y` -- data\n
 *Optional*:\n
@@ -97,7 +101,6 @@ function findpeaks(
 
     peak_info = [PeakInfo{T}(heights[i], ldiffs[i], rdiffs[i], proms[i], 1:1) for i in 1:length(inds2keep)]
 
-
     grouped = group_plateaus(peaks, peak_info, min_plateau_points, max_plateau_points)
     @on_empty_return(grouped, x)
 

test/findpeaks.jl

@@ -39,7 +39,7 @@ end
     expected_peak_1 = argmin(abs.(x .- positions[2])) # global highest peak
     expected_peak_2 = argmin(abs.(x .- positions[4])) # lowest peak
 
-    # check peaks are around expected - may be shifted because of background
+    # check peaks are around expected -> they may be shifted because of background
     @test abs(peaks[1] - expected_peak_1) < 20
     @test abs(peaks[2] - expected_peak_2) < 20
 end
@@ -93,6 +93,12 @@ end
     @test Set(findpeaks(y)[1]) == Set([4])
 end
 
+@testset "$NAME Threshold with height" begin
+    y = [0., 1., 3., 2., 4., 2., 1., 0.]
+    @test Set(findpeaks(y, min_height=2.9)[1]) == Set([3, 5])
+    @test Set(findpeaks(y, min_height=2.9, threshold=2.)[1]) == Set([5])
+end
+
 @testset "$NAME Empty inputs" begin
     y1 = Float64[]
     x1 = Int64[]