R Under development (unstable) (2023-12-07 r85661 ucrt) -- "Unsuffered Consequences"
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> library(bbmle)
Loading required package: stats4
> library(testthat)
> x <- 0:10
> y <- c(26, 17, 13, 12, 20, 5, 9, 8, 5, 4, 8)
> d <- data.frame(x,y)
> LL <- function(ymax=15, xhalf=6)
+     -sum(stats::dpois(y, lambda=ymax/(1+x/xhalf), log=TRUE))
> mfit0 <- mle2(y~dpois(lambda=exp(interc)),
+               start=list(interc=log(mean(y))),data=d)
> 
> mfit1 <- mle2(y~dpois(lambda=exp(loglambda)),
+               start=list(loglambda=log(mean(y))),data=d)
>               
> gfit0 <- glm(y~1,family=poisson)
> expect_equal(unname(coef(mfit0)),unname(coef(gfit0)))
> expect_equal(logLik(mfit0),logLik(gfit0))
> expect_equal(predict(mfit0),  ## only one value for now
+              unique(predict(gfit0,type="response")))
> 
> ## FIXME: residuals are backwards
> expect_equal(residuals(mfit0,type="response"),unname(residuals(gfit0,type="response")))
> ## FIXME: residuals are backwards
> expect_equal(residuals(mfit0,type="pearson"),unname(residuals(gfit0,type="pearson")))
> 
> 
> 
> proc.time()
   user  system elapsed 
   2.57    0.21    2.79