Early Years Foundation Stage (EYFS)
At the end of EYFS (the reception year) all pupils are assessed against the early learning goals. Children will either achieve a Good Level of Development or not. 
Phonics Screening Check
The statutory phonics screening check is a short, simple assessment to make sure that all pupils have learned phonic decoding to an appropriate standard by the age of 6. The phonics check will help teachers identify the children who need extra help so they can receive the support they need to improve their reading skills. These children will be able to retake the check in Year 2. The check comprises a list of 40 words and non-words which the child will read one-to-one with a teacher. 
Key Stage 1 Standard Assessment Tests (SATs)
SATs take place in Year 2 (at the end of infants). Each child is teacher assessed in Reading, Writing (including grammar, spelling and handwriting), Mathematics and Science. Your child's teacher will set short pieces of work in English and Maths during May to judge what level of ability your child is considered to be. 
Key Stage 2 SATs
SATs take place in May and are far more formal than Key Stage 1, hence they seem much more stressful! The test which are taken in Year 6 cover English and Mathematics. The papers are sent to be marked with results being available before your child leaves primary school in July. Writing is assessed by the teacher.